diff --git a/CHANGELOG.md b/CHANGELOG.md
index d5d58c8293b..fc12fea8208 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -22,6 +22,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
   ([#2464](https://github.com/open-telemetry/opentelemetry-python/pull/2464))
 - Fix `OTEL_EXPORTER_OTLP_ENDPOINT` usage in OTLP HTTP trace exporter 
   ([#2493](https://github.com/open-telemetry/opentelemetry-python/pull/2493))
+- [exporter/opentelemetry-exporter-prometheus] restore package using the new metrics API
+  ([#2321](https://github.com/open-telemetry/opentelemetry-python/pull/2321))
 
 ## [1.9.1-0.28b1](https://github.com/open-telemetry/opentelemetry-python/releases/tag/v1.9.1-0.28b1) - 2022-01-29
 
diff --git a/eachdist.ini b/eachdist.ini
index 576d46a5fc7..f65be079bec 100644
--- a/eachdist.ini
+++ b/eachdist.ini
@@ -35,6 +35,7 @@ version=0.28b1
 packages=
     opentelemetry-opentracing-shim
     opentelemetry-exporter-opencensus
+    opentelemetry-exporter-prometheus
     opentelemetry-distro
     opentelemetry-semantic-conventions
     opentelemetry-test-utils
@@ -45,7 +46,6 @@ version=1.10a0
 
 packages=
     opentelemetry-exporter-prometheus-remote-write
-    opentelemetry-exporter-prometheus
     opentelemetry-api
     opentelemetry-sdk
     opentelemetry-exporter-otlp-proto-grpc
diff --git a/exporter/opentelemetry-exporter-prometheus/LICENSE b/exporter/opentelemetry-exporter-prometheus/LICENSE
new file mode 100644
index 00000000000..1ef7dad2c5c
--- /dev/null
+++ b/exporter/opentelemetry-exporter-prometheus/LICENSE
@@ -0,0 +1,201 @@
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
+
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
+
+      "Licensor" shall mean the copyright owner or entity authorized by
+      the copyright owner that is granting the License.
+
+      "Legal Entity" shall mean the union of the acting entity and all
+      other entities that control, are controlled by, or are under common
+      control with that entity. For the purposes of this definition,
+      "control" means (i) the power, direct or indirect, to cause the
+      direction or management of such entity, whether by contract or
+      otherwise, or (ii) ownership of fifty percent (50%) or more of the
+      outstanding shares, or (iii) beneficial ownership of such entity.
+
+      "You" (or "Your") shall mean an individual or Legal Entity
+      exercising permissions granted by this License.
+
+      "Source" form shall mean the preferred form for making modifications,
+      including but not limited to software source code, documentation
+      source, and configuration files.
+
+      "Object" form shall mean any form resulting from mechanical
+      transformation or translation of a Source form, including but
+      not limited to compiled object code, generated documentation,
+      and conversions to other media types.
+
+      "Work" shall mean the work of authorship, whether in Source or
+      Object form, made available under the License, as indicated by a
+      copyright notice that is included in or attached to the work
+      (an example is provided in the Appendix below).
+
+      "Derivative Works" shall mean any work, whether in Source or Object
+      form, that is based on (or derived from) the Work and for which the
+      editorial revisions, annotations, elaborations, or other modifications
+      represent, as a whole, an original work of authorship. For the purposes
+      of this License, Derivative Works shall not include works that remain
+      separable from, or merely link (or bind by name) to the interfaces of,
+      the Work and Derivative Works thereof.
+
+      "Contribution" shall mean any work of authorship, including
+      the original version of the Work and any modifications or additions
+      to that Work or Derivative Works thereof, that is intentionally
+      submitted to Licensor for inclusion in the Work by the copyright owner
+      or by an individual or Legal Entity authorized to submit on behalf of
+      the copyright owner. For the purposes of this definition, "submitted"
+      means any form of electronic, verbal, or written communication sent
+      to the Licensor or its representatives, including but not limited to
+      communication on electronic mailing lists, source code control systems,
+      and issue tracking systems that are managed by, or on behalf of, the
+      Licensor for the purpose of discussing and improving the Work, but
+      excluding communication that is conspicuously marked or otherwise
+      designated in writing by the copyright owner as "Not a Contribution."
+
+      "Contributor" shall mean Licensor and any individual or Legal Entity
+      on behalf of whom a Contribution has been received by Licensor and
+      subsequently incorporated within the Work.
+
+   2. Grant of Copyright License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      copyright license to reproduce, prepare Derivative Works of,
+      publicly display, publicly perform, sublicense, and distribute the
+      Work and such Derivative Works in Source or Object form.
+
+   3. Grant of Patent License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      (except as stated in this section) patent license to make, have made,
+      use, offer to sell, sell, import, and otherwise transfer the Work,
+      where such license applies only to those patent claims licensable
+      by such Contributor that are necessarily infringed by their
+      Contribution(s) alone or by combination of their Contribution(s)
+      with the Work to which such Contribution(s) was submitted. If You
+      institute patent litigation against any entity (including a
+      cross-claim or counterclaim in a lawsuit) alleging that the Work
+      or a Contribution incorporated within the Work constitutes direct
+      or contributory patent infringement, then any patent licenses
+      granted to You under this License for that Work shall terminate
+      as of the date such litigation is filed.
+
+   4. Redistribution. You may reproduce and distribute copies of the
+      Work or Derivative Works thereof in any medium, with or without
+      modifications, and in Source or Object form, provided that You
+      meet the following conditions:
+
+      (a) You must give any other recipients of the Work or
+          Derivative Works a copy of this License; and
+
+      (b) You must cause any modified files to carry prominent notices
+          stating that You changed the files; and
+
+      (c) You must retain, in the Source form of any Derivative Works
+          that You distribute, all copyright, patent, trademark, and
+          attribution notices from the Source form of the Work,
+          excluding those notices that do not pertain to any part of
+          the Derivative Works; and
+
+      (d) If the Work includes a "NOTICE" text file as part of its
+          distribution, then any Derivative Works that You distribute must
+          include a readable copy of the attribution notices contained
+          within such NOTICE file, excluding those notices that do not
+          pertain to any part of the Derivative Works, in at least one
+          of the following places: within a NOTICE text file distributed
+          as part of the Derivative Works; within the Source form or
+          documentation, if provided along with the Derivative Works; or,
+          within a display generated by the Derivative Works, if and
+          wherever such third-party notices normally appear. The contents
+          of the NOTICE file are for informational purposes only and
+          do not modify the License. You may add Your own attribution
+          notices within Derivative Works that You distribute, alongside
+          or as an addendum to the NOTICE text from the Work, provided
+          that such additional attribution notices cannot be construed
+          as modifying the License.
+
+      You may add Your own copyright statement to Your modifications and
+      may provide additional or different license terms and conditions
+      for use, reproduction, or distribution of Your modifications, or
+      for any such Derivative Works as a whole, provided Your use,
+      reproduction, and distribution of the Work otherwise complies with
+      the conditions stated in this License.
+
+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
+      except as required for reasonable and customary use in describing the
+      origin of the Work and reproducing the content of the NOTICE file.
+
+   7. Disclaimer of Warranty. Unless required by applicable law or
+      agreed to in writing, Licensor provides the Work (and each
+      Contributor provides its Contributions) on an "AS IS" BASIS,
+      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+      implied, including, without limitation, any warranties or conditions
+      of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
+      PARTICULAR PURPOSE. You are solely responsible for determining the
+      appropriateness of using or redistributing the Work and assume any
+      risks associated with Your exercise of permissions under this License.
+
+   8. Limitation of Liability. In no event and under no legal theory,
+      whether in tort (including negligence), contract, or otherwise,
+      unless required by applicable law (such as deliberate and grossly
+      negligent acts) or agreed to in writing, shall any Contributor be
+      liable to You for damages, including any direct, indirect, special,
+      incidental, or consequential damages of any character arising as a
+      result of this License or out of the use or inability to use the
+      Work (including but not limited to damages for loss of goodwill,
+      work stoppage, computer failure or malfunction, or any and all
+      other commercial damages or losses), even if such Contributor
+      has been advised of the possibility of such damages.
+
+   9. Accepting Warranty or Additional Liability. While redistributing
+      the Work or Derivative Works thereof, You may choose to offer,
+      and charge a fee for, acceptance of support, warranty, indemnity,
+      or other liability obligations and/or rights consistent with this
+      License. However, in accepting such obligations, You may act only
+      on Your own behalf and on Your sole responsibility, not on behalf
+      of any other Contributor, and only if You agree to indemnify,
+      defend, and hold each Contributor harmless for any liability
+      incurred by, or claims asserted against, such Contributor by reason
+      of your accepting any such warranty or additional liability.
+
+   END OF TERMS AND CONDITIONS
+
+   APPENDIX: How to apply the Apache License to your work.
+
+      To apply the Apache License to your work, attach the following
+      boilerplate notice, with the fields enclosed by brackets "[]"
+      replaced with your own identifying information. (Don't include
+      the brackets!)  The text should be enclosed in the appropriate
+      comment syntax for the file format. We also recommend that a
+      file or class name and description of purpose be included on the
+      same "printed page" as the copyright notice for easier
+      identification within third-party archives.
+
+   Copyright The OpenTelemetry Authors
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
diff --git a/exporter/opentelemetry-exporter-prometheus/MANIFEST.in b/exporter/opentelemetry-exporter-prometheus/MANIFEST.in
new file mode 100644
index 00000000000..aed3e33273b
--- /dev/null
+++ b/exporter/opentelemetry-exporter-prometheus/MANIFEST.in
@@ -0,0 +1,9 @@
+graft src
+graft tests
+global-exclude *.pyc
+global-exclude *.pyo
+global-exclude __pycache__/*
+include CHANGELOG.md
+include MANIFEST.in
+include README.rst
+include LICENSE
diff --git a/exporter/opentelemetry-exporter-prometheus/README.rst b/exporter/opentelemetry-exporter-prometheus/README.rst
new file mode 100644
index 00000000000..a3eb9200005
--- /dev/null
+++ b/exporter/opentelemetry-exporter-prometheus/README.rst
@@ -0,0 +1,23 @@
+OpenTelemetry Prometheus Exporter
+=================================
+
+|pypi|
+
+.. |pypi| image:: https://badge.fury.io/py/opentelemetry-exporter-prometheus.svg
+   :target: https://pypi.org/project/opentelemetry-exporter-prometheus/
+
+This library allows to export metrics data to `Prometheus <https://prometheus.io/>`_.
+
+Installation
+------------
+
+::
+
+     pip install opentelemetry-exporter-prometheus
+
+References
+----------
+
+* `OpenTelemetry Prometheus Exporter <https://opentelemetry-python.readthedocs.io/en/latest/exporter/prometheus/prometheus.html>`_
+* `Prometheus <https://prometheus.io/>`_
+* `OpenTelemetry Project <https://opentelemetry.io/>`_
diff --git a/exporter/opentelemetry-exporter-prometheus/setup.cfg b/exporter/opentelemetry-exporter-prometheus/setup.cfg
new file mode 100644
index 00000000000..53e9ef17ede
--- /dev/null
+++ b/exporter/opentelemetry-exporter-prometheus/setup.cfg
@@ -0,0 +1,55 @@
+# Copyright The OpenTelemetry Authors
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+[metadata]
+name = opentelemetry-exporter-prometheus
+description = Prometheus Metric Exporter for OpenTelemetry
+long_description = file: README.rst
+long_description_content_type = text/x-rst
+author = OpenTelemetry Authors
+author_email = cncf-opentelemetry-contributors@lists.cncf.io
+url = https://github.com/open-telemetry/opentelemetry-python/tree/main/exporter/opentelemetry-exporter-prometheus
+platforms = any
+license = Apache-2.0
+classifiers =
+    Development Status :: 4 - Beta
+    Intended Audience :: Developers
+    License :: OSI Approved :: Apache Software License
+    Programming Language :: Python
+    Programming Language :: Python :: 3
+    Programming Language :: Python :: 3.6
+    Programming Language :: Python :: 3.7
+    Programming Language :: Python :: 3.8
+    Programming Language :: Python :: 3.9
+    Programming Language :: Python :: 3.10
+
+[options]
+python_requires = >=3.6
+package_dir=
+    =src
+packages=find_namespace:
+install_requires =
+    prometheus_client >= 0.5.0, < 1.0.0
+    opentelemetry-api >= 1.9.1
+    opentelemetry-sdk >= 1.9.1
+
+[options.packages.find]
+where = src
+
+[options.extras_require]
+test =
+
+[options.entry_points]
+opentelemetry_metric_reader =
+    prometheus = opentelemetry.exporter.prometheus:PrometheusMetricReader
diff --git a/exporter/opentelemetry-exporter-prometheus/setup.py b/exporter/opentelemetry-exporter-prometheus/setup.py
new file mode 100644
index 00000000000..9fdbd7de497
--- /dev/null
+++ b/exporter/opentelemetry-exporter-prometheus/setup.py
@@ -0,0 +1,26 @@
+# Copyright The OpenTelemetry Authors
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+import os
+
+import setuptools
+
+_BASE_DIR = os.path.dirname(__file__)
+_VERSION_FILENAME = os.path.join(
+    _BASE_DIR, "src", "opentelemetry", "exporter", "prometheus", "version.py"
+)
+_PACKAGE_INFO = {}
+with open(_VERSION_FILENAME, encoding="utf-8") as f:
+    exec(f.read(), _PACKAGE_INFO)
+
+setuptools.setup(version=_PACKAGE_INFO["__version__"])
diff --git a/exporter/opentelemetry-exporter-prometheus/src/opentelemetry/exporter/prometheus/__init__.py b/exporter/opentelemetry-exporter-prometheus/src/opentelemetry/exporter/prometheus/__init__.py
new file mode 100644
index 00000000000..a952e56bcf8
--- /dev/null
+++ b/exporter/opentelemetry-exporter-prometheus/src/opentelemetry/exporter/prometheus/__init__.py
@@ -0,0 +1,208 @@
+# Copyright The OpenTelemetry Authors
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""
+This library allows export of metrics data to `Prometheus <https://prometheus.io/>`_.
+
+Usage
+-----
+
+The **OpenTelemetry Prometheus Exporter** allows export of `OpenTelemetry`_
+metrics to `Prometheus`_.
+
+
+.. _Prometheus: https://prometheus.io/
+.. _OpenTelemetry: https://github.com/open-telemetry/opentelemetry-python/
+
+.. code:: python
+
+    from prometheus_client import start_http_server
+
+    from opentelemetry._metrics import get_meter_provider, set_meter_provider
+    from opentelemetry.exporter.prometheus import PrometheusMetricReader
+    from opentelemetry.sdk._metrics import MeterProvider
+
+    # Start Prometheus client
+    start_http_server(port=8000, addr="localhost")
+
+    # Exporter to export metrics to Prometheus
+    prefix = "MyAppPrefix"
+    reader = PrometheusMetricReader(prefix)
+
+    # Meter is responsible for creating and recording metrics
+    set_meter_provider(MeterProvider(metric_readers=[reader]))
+    meter = get_meter_provider().get_meter("myapp", "0.1.2")
+
+    counter = meter.create_counter(
+        "requests",
+        "requests",
+        "number of requests",
+    )
+
+    # Labels are used to identify key-values that are associated with a specific
+    # metric that you want to record. These are useful for pre-aggregation and can
+    # be used to store custom dimensions pertaining to a metric
+    labels = {"environment": "staging"}
+
+    counter.add(25, labels)
+    input("Press any key to exit...")
+
+API
+---
+"""
+
+import collections
+import logging
+import re
+from typing import Iterable, Optional, Sequence, Tuple
+
+from prometheus_client import core
+
+from opentelemetry.sdk._metrics.export import MetricReader
+from opentelemetry.sdk._metrics.point import Gauge, Histogram, Metric, Sum
+
+_logger = logging.getLogger(__name__)
+
+
+def _convert_buckets(metric: Metric) -> Sequence[Tuple[str, int]]:
+    buckets = []
+    total_count = 0
+    for index, value in enumerate(metric.point.bucket_counts):
+        total_count += value
+        buckets.append(
+            (
+                f"{metric.point.explicit_bounds[index]}",
+                total_count,
+            )
+        )
+    return buckets
+
+
+class PrometheusMetricReader(MetricReader):
+    """Prometheus metric exporter for OpenTelemetry.
+
+    Args:
+        prefix: single-word application prefix relevant to the domain
+            the metric belongs to.
+    """
+
+    def __init__(self, prefix: str = "") -> None:
+        super().__init__()
+        self._collector = _CustomCollector(prefix)
+        core.REGISTRY.register(self._collector)
+        self._collector._callback = self.collect
+
+    def _receive_metrics(self, metrics: Iterable[Metric]) -> None:
+        if metrics is None:
+            return
+        self._collector.add_metrics_data(metrics)
+
+    def shutdown(self) -> bool:
+        core.REGISTRY.unregister(self._collector)
+        return True
+
+
+class _CustomCollector:
+    """_CustomCollector represents the Prometheus Collector object
+
+    See more:
+    https://github.com/prometheus/client_python#custom-collectors
+    """
+
+    def __init__(self, prefix: str = ""):
+        self._prefix = prefix
+        self._callback = None
+        self._metrics_to_export = collections.deque()
+        self._non_letters_digits_underscore_re = re.compile(
+            r"[^\w]", re.UNICODE | re.IGNORECASE
+        )
+
+    def add_metrics_data(self, export_records: Sequence[Metric]) -> None:
+        """Add metrics to Prometheus data"""
+        self._metrics_to_export.append(export_records)
+
+    def collect(self) -> None:
+        """Collect fetches the metrics from OpenTelemetry
+        and delivers them as Prometheus Metrics.
+        Collect is invoked every time a ``prometheus.Gatherer`` is run
+        for example when the HTTP endpoint is invoked by Prometheus.
+        """
+        if self._callback is not None:
+            self._callback()
+
+        while self._metrics_to_export:
+            for export_record in self._metrics_to_export.popleft():
+                prometheus_metric = self._translate_to_prometheus(
+                    export_record
+                )
+                if prometheus_metric is not None:
+                    yield prometheus_metric
+
+    def _translate_to_prometheus(
+        self, metric: Metric
+    ) -> Optional[core.Metric]:
+        prometheus_metric = None
+        label_values = []
+        label_keys = []
+        for key, value in metric.attributes.items():
+            label_keys.append(self._sanitize(key))
+            label_values.append(str(value))
+
+        metric_name = ""
+        if self._prefix != "":
+            metric_name = self._prefix + "_"
+        metric_name += self._sanitize(metric.name)
+
+        description = metric.description or ""
+        if isinstance(metric.point, Sum):
+            prometheus_metric = core.CounterMetricFamily(
+                name=metric_name,
+                documentation=description,
+                labels=label_keys,
+                unit=metric.unit,
+            )
+            prometheus_metric.add_metric(
+                labels=label_values, value=metric.point.value
+            )
+        elif isinstance(metric.point, Gauge):
+            prometheus_metric = core.GaugeMetricFamily(
+                name=metric_name,
+                documentation=description,
+                labels=label_keys,
+                unit=metric.unit,
+            )
+            prometheus_metric.add_metric(
+                labels=label_values, value=metric.point.value
+            )
+        elif isinstance(metric.point, Histogram):
+            value = metric.point.sum
+            prometheus_metric = core.HistogramMetricFamily(
+                name=metric_name,
+                documentation=description,
+                labels=label_keys,
+                unit=metric.unit,
+            )
+            buckets = _convert_buckets(metric)
+            prometheus_metric.add_metric(
+                labels=label_values, buckets=buckets, sum_value=value
+            )
+        else:
+            _logger.warning("Unsupported metric type. %s", type(metric.point))
+        return prometheus_metric
+
+    def _sanitize(self, key: str) -> str:
+        """sanitize the given metric name or label according to Prometheus rule.
+        Replace all characters other than [A-Za-z0-9_] with '_'.
+        """
+        return self._non_letters_digits_underscore_re.sub("_", key)
diff --git a/exporter/opentelemetry-exporter-prometheus/src/opentelemetry/exporter/prometheus/version.py b/exporter/opentelemetry-exporter-prometheus/src/opentelemetry/exporter/prometheus/version.py
new file mode 100644
index 00000000000..a94d4ed4462
--- /dev/null
+++ b/exporter/opentelemetry-exporter-prometheus/src/opentelemetry/exporter/prometheus/version.py
@@ -0,0 +1,15 @@
+# Copyright The OpenTelemetry Authors
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+__version__ = "0.28b1"
diff --git a/exporter/opentelemetry-exporter-prometheus/tests/__init__.py b/exporter/opentelemetry-exporter-prometheus/tests/__init__.py
new file mode 100644
index 00000000000..b0a6f428417
--- /dev/null
+++ b/exporter/opentelemetry-exporter-prometheus/tests/__init__.py
@@ -0,0 +1,13 @@
+# Copyright The OpenTelemetry Authors
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
diff --git a/exporter/opentelemetry-exporter-prometheus/tests/test_prometheus_exporter.py b/exporter/opentelemetry-exporter-prometheus/tests/test_prometheus_exporter.py
new file mode 100644
index 00000000000..af4bc7c0fdd
--- /dev/null
+++ b/exporter/opentelemetry-exporter-prometheus/tests/test_prometheus_exporter.py
@@ -0,0 +1,154 @@
+# Copyright The OpenTelemetry Authors
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import unittest
+from unittest import mock
+
+from prometheus_client import generate_latest
+from prometheus_client.core import CounterMetricFamily, GaugeMetricFamily
+
+from opentelemetry.exporter.prometheus import (
+    PrometheusMetricReader,
+    _CustomCollector,
+)
+from opentelemetry.sdk._metrics.point import AggregationTemporality, Histogram
+from opentelemetry.test.metrictestutil import (
+    _generate_gauge,
+    _generate_metric,
+    _generate_sum,
+    _generate_unsupported_metric,
+)
+
+
+class TestPrometheusMetricReader(unittest.TestCase):
+    def setUp(self):
+        self._mock_registry_register = mock.Mock()
+        self._registry_register_patch = mock.patch(
+            "prometheus_client.core.REGISTRY.register",
+            side_effect=self._mock_registry_register,
+        )
+
+    # pylint: disable=protected-access
+    def test_constructor(self):
+        """Test the constructor."""
+        with self._registry_register_patch:
+            exporter = PrometheusMetricReader("testprefix")
+            self.assertEqual(exporter._collector._prefix, "testprefix")
+            self.assertTrue(self._mock_registry_register.called)
+
+    def test_shutdown(self):
+        with mock.patch(
+            "prometheus_client.core.REGISTRY.unregister"
+        ) as registry_unregister_patch:
+            exporter = PrometheusMetricReader()
+            exporter.shutdown()
+            self.assertTrue(registry_unregister_patch.called)
+
+    def test_histogram_to_prometheus(self):
+        record = _generate_metric(
+            "test@name",
+            Histogram(
+                time_unix_nano=1641946016139533244,
+                start_time_unix_nano=1641946016139533244,
+                bucket_counts=[1, 1],
+                sum=579.0,
+                explicit_bounds=[123.0, 456.0],
+                aggregation_temporality=AggregationTemporality.DELTA,
+            ),
+            attributes={"histo": 1},
+        )
+
+        collector = _CustomCollector("testprefix")
+        collector.add_metrics_data([record])
+        result_bytes = generate_latest(collector)
+        result = result_bytes.decode("utf-8")
+        self.assertIn('testprefix_test_name_s_sum{histo="1"} 579.0', result)
+        self.assertIn('testprefix_test_name_s_count{histo="1"} 2.0', result)
+
+    def test_sum_to_prometheus(self):
+        labels = {"environment@": "staging", "os": "Windows"}
+        record = _generate_sum(
+            "test@sum",
+            123,
+            attributes=labels,
+            description="testdesc",
+            unit="testunit",
+        )
+        collector = _CustomCollector("testprefix")
+        collector.add_metrics_data([record])
+
+        for prometheus_metric in collector.collect():
+            self.assertEqual(type(prometheus_metric), CounterMetricFamily)
+            self.assertEqual(
+                prometheus_metric.name, "testprefix_test_sum_testunit"
+            )
+            self.assertEqual(prometheus_metric.documentation, "testdesc")
+            self.assertTrue(len(prometheus_metric.samples) == 1)
+            self.assertEqual(prometheus_metric.samples[0].value, 123)
+            self.assertTrue(len(prometheus_metric.samples[0].labels) == 2)
+            self.assertEqual(
+                prometheus_metric.samples[0].labels["environment_"], "staging"
+            )
+            self.assertEqual(
+                prometheus_metric.samples[0].labels["os"], "Windows"
+            )
+
+    def test_gauge_to_prometheus(self):
+        labels = {"environment@": "dev", "os": "Unix"}
+        record = _generate_gauge(
+            "test@gauge",
+            123,
+            attributes=labels,
+            description="testdesc",
+            unit="testunit",
+        )
+        collector = _CustomCollector("testprefix")
+        collector.add_metrics_data([record])
+
+        for prometheus_metric in collector.collect():
+            self.assertEqual(type(prometheus_metric), GaugeMetricFamily)
+            self.assertEqual(
+                prometheus_metric.name, "testprefix_test_gauge_testunit"
+            )
+            self.assertEqual(prometheus_metric.documentation, "testdesc")
+            self.assertTrue(len(prometheus_metric.samples) == 1)
+            self.assertEqual(prometheus_metric.samples[0].value, 123)
+            self.assertTrue(len(prometheus_metric.samples[0].labels) == 2)
+            self.assertEqual(
+                prometheus_metric.samples[0].labels["environment_"], "dev"
+            )
+            self.assertEqual(prometheus_metric.samples[0].labels["os"], "Unix")
+
+    def test_invalid_metric(self):
+        labels = {"environment": "staging"}
+        record = _generate_unsupported_metric(
+            "tesname",
+            attributes=labels,
+            description="testdesc",
+            unit="testunit",
+        )
+        collector = _CustomCollector("testprefix")
+        collector.add_metrics_data([record])
+        collector.collect()
+        self.assertLogs("opentelemetry.exporter.prometheus", level="WARNING")
+
+    def test_sanitize(self):
+        collector = _CustomCollector("testprefix")
+        self.assertEqual(
+            collector._sanitize("1!2@3#4$5%6^7&8*9(0)_-"),
+            "1_2_3_4_5_6_7_8_9_0___",
+        )
+        self.assertEqual(collector._sanitize(",./?;:[]{}"), "__________")
+        self.assertEqual(collector._sanitize("TestString"), "TestString")
+        self.assertEqual(collector._sanitize("aAbBcC_12_oi"), "aAbBcC_12_oi")
diff --git a/tox.ini b/tox.ini
index 44c4367588d..8d5973b166f 100644
--- a/tox.ini
+++ b/tox.ini
@@ -42,6 +42,9 @@ envlist =
     py3{6,7,8,9,10}-opentelemetry-exporter-otlp-proto-http
     pypy3-opentelemetry-exporter-otlp-proto-http
 
+    py3{6,7,8,9,10}-opentelemetry-exporter-prometheus
+    pypy3-opentelemetry-exporter-prometheus
+
     ; opentelemetry-exporter-zipkin
     py3{6,7,8,9,10}-opentelemetry-exporter-zipkin-combined
     pypy3-opentelemetry-exporter-zipkin-combined
@@ -97,6 +100,7 @@ changedir =
   exporter-otlp-combined: exporter/opentelemetry-exporter-otlp/tests
   exporter-otlp-proto-grpc: exporter/opentelemetry-exporter-otlp-proto-grpc/tests
   exporter-otlp-proto-http: exporter/opentelemetry-exporter-otlp-proto-http/tests
+  exporter-prometheus: exporter/opentelemetry-exporter-prometheus/tests
   exporter-zipkin-combined: exporter/opentelemetry-exporter-zipkin/tests
   exporter-zipkin-proto-http: exporter/opentelemetry-exporter-zipkin-proto-http/tests
   exporter-zipkin-json: exporter/opentelemetry-exporter-zipkin-json/tests
@@ -140,6 +144,8 @@ commands_pre =
   opentracing-shim: pip install {toxinidir}/opentelemetry-sdk
   opentracing-shim: pip install {toxinidir}/shim/opentelemetry-opentracing-shim
 
+  exporter-prometheus: pip install {toxinidir}/exporter/opentelemetry-exporter-prometheus
+
   exporter-zipkin-combined: pip install {toxinidir}/exporter/opentelemetry-exporter-zipkin-json
   exporter-zipkin-combined: pip install {toxinidir}/exporter/opentelemetry-exporter-zipkin-proto-http
   exporter-zipkin-combined: pip install {toxinidir}/exporter/opentelemetry-exporter-zipkin
@@ -202,6 +208,7 @@ commands_pre =
   python -m pip install -e {toxinidir}/exporter/opentelemetry-exporter-otlp-proto-grpc[test]
   python -m pip install -e {toxinidir}/exporter/opentelemetry-exporter-otlp-proto-http[test]
   python -m pip install -e {toxinidir}/exporter/opentelemetry-exporter-otlp[test]
+  python -m pip install -e {toxinidir}/exporter/opentelemetry-exporter-prometheus[test]
   python -m pip install -e {toxinidir}/exporter/opentelemetry-exporter-zipkin-json[test]
   python -m pip install -e {toxinidir}/exporter/opentelemetry-exporter-zipkin-proto-http[test]
   python -m pip install -e {toxinidir}/exporter/opentelemetry-exporter-zipkin[test]