diff --git a/configs/data/dataset.yaml b/configs/data/dataset.yaml
index e13fec8..172e48f 100644
--- a/configs/data/dataset.yaml
+++ b/configs/data/dataset.yaml
@@ -14,6 +14,8 @@ dataset:
     test_split_filename: "split_mapping/test_split.csv"
     tiling_run_id: "fdf7550a2004474f8c7a05dc0cf1fd86"
     filter_tiles_run_id: "4e8f5d3c82124ea5a8f871a42d3ed9ba"
+    kfold_run_id: "850c81506684450b9af92296acfd045a"
+    embedding_run_id: "c325e3a5033b4077b6febb0e3e6b0bd6"
     tissue_masks_run_id: "52bc0924f8624b259819c480c7cf213f"
     tissue_stats_run_id: "16ae2d003d88471b924e5f332415232a"
 
diff --git a/configs/experiment/preprocessing/embedding_dataset.yaml b/configs/experiment/preprocessing/embedding_dataset.yaml
new file mode 100644
index 0000000..8004e2e
--- /dev/null
+++ b/configs/experiment/preprocessing/embedding_dataset.yaml
@@ -0,0 +1,23 @@
+# @package _global_
+
+defaults:
+  - /data: dataset
+  - _self_
+
+tissue_prop_min: 0.2
+thresholds:
+  Nerve: 0.0
+  Blood: 0.0
+  Connective-Tissue: 0.4
+  Fat: 0.5
+  Epithelium: 0.2
+  Muscle: 0.4
+  Other: 0.5
+
+metadata:
+  run_name: Embedding dataset ${dataset.name}
+  description: "Join k-fold (${dataset.mlflow_artifacts.kfold_run_id}) and filter_tiles (${dataset.mlflow_artifacts.filter_tiles_run_id}) tile metadata with embeddings (${dataset.mlflow_artifacts.embedding_run_id})."
+  hyperparams:
+    kfold_run_id: ${dataset.mlflow_artifacts.kfold_run_id}
+    filter_tiles_run_id: ${dataset.mlflow_artifacts.filter_tiles_run_id}
+    embedding_run_id: ${dataset.mlflow_artifacts.embedding_run_id}
diff --git a/configs/preprocessing/embedding_dataset.yaml b/configs/preprocessing/embedding_dataset.yaml
new file mode 100644
index 0000000..f4af56a
--- /dev/null
+++ b/configs/preprocessing/embedding_dataset.yaml
@@ -0,0 +1,13 @@
+# @package _global_
+
+mlflow_artifact_path: embedding_dataset
+
+tissue_prop_min: ???
+thresholds: ???
+
+metadata:
+  run_name: "Embedding dataset ${dataset.name}"
+  description: "Build embedding training dataset by joining k-fold/filter_tiles tile metadata with precomputed embeddings."
+  hyperparams:
+    tissue_prop_min: ${tissue_prop_min}
+    thresholds: ${thresholds}
diff --git a/preprocessing/_labels.py b/preprocessing/_labels.py
new file mode 100644
index 0000000..229f7dc
--- /dev/null
+++ b/preprocessing/_labels.py
@@ -0,0 +1,24 @@
+"""Shared helpers for deriving tile labels from roi_coverage_* columns."""
+
+from collections.abc import Mapping
+from typing import Any
+
+import numpy as np
+import pandas as pd
+
+
+def compute_label_and_tissue_prop(
+    roi_data: Mapping[str, Any],
+    roi_cols: list[str],
+) -> tuple[np.ndarray, np.ndarray]:
+    """Compute (label, tissue_prop) from roi_coverage_* columns.
+
+    label = argmax across roi_cols (with ``roi_coverage_`` prefix stripped),
+    falling back to ``"background"`` whenever all coverages are zero.
+    tissue_prop = sum across roi_cols.
+    """
+    roi_df = pd.DataFrame({col: roi_data[col] for col in roi_cols})
+    tp = roi_df.sum(axis=1).to_numpy()
+    lbl = roi_df.idxmax(axis=1).str.removeprefix("roi_coverage_").to_numpy()
+    lbl[tp == 0] = "background"
+    return lbl, tp
diff --git a/preprocessing/embedding_dataset.py b/preprocessing/embedding_dataset.py
new file mode 100644
index 0000000..f32f51d
--- /dev/null
+++ b/preprocessing/embedding_dataset.py
@@ -0,0 +1,283 @@
+"""Build an embedding training dataset by joining tile metadata with embeddings.
+
+Joins precomputed tile embeddings with k-fold metadata (train) / filter_tiles
+metadata (test), applies tissue + per-class ROI thresholds before the join, and
+emits a training-ready Parquet dataset (per-split ``slides.parquet`` +
+``tiles.parquet``) ready for ``rationai.mlkit.data.datasets.SlidesTilesLoader``.
+"""
+
+import shutil
+import tempfile
+from pathlib import Path
+
+import hydra
+import mlflow
+import mlflow.artifacts
+import pandas as pd
+import pyarrow as pa
+import pyarrow.compute as pc
+import pyarrow.dataset as pads
+import pyarrow.parquet as pq
+from omegaconf import DictConfig, OmegaConf
+from rationai.mlkit import autolog, with_cli_args
+from rationai.mlkit.lightning.loggers import MLFlowLogger
+
+from preprocessing._labels import compute_label_and_tissue_prop
+
+
+def apply_thresholds(
+    df: pd.DataFrame,
+    tissue_prop_min: float,
+    thresholds: dict[str, float],
+    roi_cols: list[str],
+) -> tuple[pd.DataFrame, int, int]:
+    """Filter tiles by tissue, drop multi-annotation tiles, then apply argmax-then-threshold.
+
+    Returns ``(filtered_df, after_tissue_count, after_single_class_count)``.
+    """
+    df = df.loc[df["tissue_prop"] >= tissue_prop_min]
+    after_tissue = len(df)
+    if df.empty:
+        return df, after_tissue, after_tissue
+
+    nonzero_classes = (df[roi_cols].to_numpy() > 0).sum(axis=1)
+    df = df.loc[pd.Series(nonzero_classes <= 1, index=df.index)]
+    after_single_class = len(df)
+    if df.empty:
+        return df, after_tissue, after_single_class
+
+    roi_only = df[roi_cols]
+    dominant = roi_only.idxmax(axis=1).str.removeprefix("roi_coverage_")
+    dominant_value = roi_only.max(axis=1).to_numpy()
+    threshold_per_row = dominant.map(thresholds).to_numpy()
+    keep = dominant_value >= threshold_per_row
+
+    out = df.loc[pd.Series(keep, index=df.index)].copy()
+    out["label"] = dominant.to_numpy()[keep]
+    return out, after_tissue, after_single_class
+
+
+def join_embeddings(
+    tiles_table: pa.Table,
+    embedding_run_id: str,
+    embedding_split: str,
+) -> tuple[pa.Table, int]:
+    """Join filtered tile metadata with embeddings on (slide_id, x, y).
+
+    Stays in Arrow throughout to avoid the very slow list<double> -> pandas
+    conversion. Acero's join engine doesn't accept list columns in non-key
+    fields, so we join on keys plus a synthetic row index, then pull embeddings
+    via take(). The embedding column is cast per chunk to large_list to avoid
+    int32 offset overflow that bites take() when chunks are concatenated.
+    """
+    emb_dir = mlflow.artifacts.download_artifacts(
+        run_id=embedding_run_id, artifact_path=f"{embedding_split}/tiles"
+    )
+    emb_table = pads.dataset(emb_dir, format="parquet").to_table(
+        columns=["slide_id", "x", "y", "embedding"]
+    )
+
+    emb_col = emb_table.column("embedding")
+    if pa.types.is_list(emb_col.type):
+        target_type = pa.large_list(emb_col.type.value_type)
+        emb_col = pa.chunked_array(
+            [c.cast(target_type) for c in emb_col.chunks], type=target_type
+        )
+
+    emb_idx = pa.array(range(emb_table.num_rows), type=pa.int64())
+    emb_keys = emb_table.drop(["embedding"]).append_column("_emb_idx", emb_idx)
+    del emb_table, emb_idx
+
+    joined_keys = tiles_table.join(
+        emb_keys, keys=["slide_id", "x", "y"], join_type="inner"
+    )
+    del emb_keys
+
+    indices = joined_keys.column("_emb_idx")
+    if isinstance(indices, pa.ChunkedArray):
+        indices = indices.combine_chunks()
+
+    emb_contig = emb_col.combine_chunks()
+    del emb_col
+
+    embeddings = emb_contig.take(indices)
+    del emb_contig
+
+    joined = joined_keys.drop(["_emb_idx"]).append_column("embedding", embeddings)
+    dropped_no_embedding = tiles_table.num_rows - joined.num_rows
+    return joined, dropped_no_embedding
+
+
+def process_split(
+    split_name: str,
+    src_run_id: str,
+    src_artifact_path: str,
+    embedding_run_id: str,
+    tissue_prop_min: float,
+    thresholds: dict[str, float],
+    output_split_dir: Path,
+    derive: bool,
+) -> dict[str, int]:
+    print(f"[{split_name}] downloading source tiles", flush=True)
+    src_local = mlflow.artifacts.download_artifacts(
+        run_id=src_run_id, artifact_path=src_artifact_path
+    )
+    df = pads.dataset(src_local, format="parquet").to_table().to_pandas()
+    input_count = len(df)
+
+    roi_cols = [c for c in df.columns if c.startswith("roi_coverage_")]
+    if not roi_cols:
+        raise RuntimeError(
+            f"No roi_coverage_* columns in {src_artifact_path}. "
+            "Cannot apply class thresholds."
+        )
+
+    classes_in_data = {c.removeprefix("roi_coverage_") for c in roi_cols}
+    missing = classes_in_data - set(thresholds.keys())
+    if missing:
+        raise ValueError(
+            f"thresholds is missing entries for roi_coverage_* classes present "
+            f"in data: {sorted(missing)}"
+        )
+
+    if derive:
+        lbl, tp = compute_label_and_tissue_prop(df, roi_cols)
+        df["label"] = lbl
+        df["tissue_prop"] = tp
+    else:
+        required = {"label", "tissue_prop"}
+        missing_required = required - set(df.columns)
+        if missing_required:
+            raise RuntimeError(
+                f"Source split '{split_name}' (derive=False) is missing required "
+                f"columns {sorted(missing_required)} in {src_artifact_path}. "
+                "Expected the kfold_split artifact, which writes label/tissue_prop/fold."
+            )
+
+    df, after_tissue_filter, after_single_class = apply_thresholds(
+        df, tissue_prop_min, thresholds, roi_cols
+    )
+    after_class_threshold = len(df)
+    if after_class_threshold == 0:
+        raise RuntimeError(
+            f"All {input_count} tiles dropped by thresholds for split '{split_name}'."
+        )
+
+    drop_cols = [
+        c for c in df.columns if c.startswith(("roi_coverage_", "tile_coverage_"))
+    ]
+    df = df.drop(columns=drop_cols)
+    print(
+        f"[{split_name}] {input_count} -> {after_tissue_filter} (tissue) "
+        f"-> {after_single_class} (single-class) "
+        f"-> {after_class_threshold} (class threshold), joining embeddings",
+        flush=True,
+    )
+
+    tiles_table = pa.Table.from_pandas(df, preserve_index=False)
+    del df
+
+    merged_table, dropped_no_embedding = join_embeddings(
+        tiles_table, embedding_run_id, split_name
+    )
+    del tiles_table
+    if dropped_no_embedding != 0:
+        print(
+            f"WARNING: {dropped_no_embedding} tiles in split '{split_name}' have "
+            "no matching embedding and were dropped on join.",
+            flush=True,
+        )
+
+    sort_indices = pc.sort_indices(merged_table, sort_keys=[("slide_id", "ascending")])
+    merged_table = merged_table.take(sort_indices)
+
+    output_split_dir.mkdir(parents=True, exist_ok=True)
+    pq.write_table(merged_table, str(output_split_dir / "tiles.parquet"))
+
+    slides_local = mlflow.artifacts.download_artifacts(
+        run_id=embedding_run_id, artifact_path=f"{split_name}/slides.parquet"
+    )
+    shutil.copy(slides_local, output_split_dir / "slides.parquet")
+
+    log_label_distributions(split_name, merged_table)
+    print(f"[{split_name}] wrote {merged_table.num_rows} rows", flush=True)
+
+    return {
+        "input_count": input_count,
+        "after_tissue_filter": after_tissue_filter,
+        "after_single_class": after_single_class,
+        "after_class_threshold": after_class_threshold,
+        "after_join": merged_table.num_rows,
+        "dropped_no_embedding": dropped_no_embedding,
+    }
+
+
+def log_label_distributions(split_name: str, table: pa.Table) -> None:
+    has_fold = "fold" in table.schema.names
+    cols = ["label", "fold"] if has_fold else ["label"]
+    df = table.select(cols).to_pandas()
+
+    label_dist = (
+        df["label"].value_counts().rename_axis("label").reset_index(name="count")
+    )
+    mlflow.log_table(
+        data=label_dist,
+        artifact_file=f"fold_statistics/{split_name}_label_distribution.json",
+    )
+
+    if has_fold:
+        fold_dist = (
+            df.groupby(["fold", "label"]).size().unstack(fill_value=0).reset_index()
+        )
+        mlflow.log_table(
+            data=fold_dist,
+            artifact_file=f"fold_statistics/{split_name}_fold_label_distribution.json",
+        )
+
+
+@with_cli_args(["+preprocessing=embedding_dataset"])
+@hydra.main(config_path="../configs", config_name="preprocessing", version_base=None)
+@autolog
+def main(config: DictConfig, logger: MLFlowLogger) -> None:
+    artifacts = config.dataset.mlflow_artifacts
+    kfold_run_id = artifacts.kfold_run_id
+    filter_tiles_run_id = artifacts.filter_tiles_run_id
+    embedding_run_id = artifacts.embedding_run_id
+
+    tissue_prop_min = float(config.tissue_prop_min)
+    if tissue_prop_min <= 0:
+        raise ValueError(
+            f"tissue_prop_min must be > 0 (got {tissue_prop_min}); "
+            "otherwise background tiles are not filtered out."
+        )
+    raw_thresholds = OmegaConf.to_container(config.thresholds, resolve=True)
+    if not isinstance(raw_thresholds, dict):
+        raise TypeError("config.thresholds must be a mapping of class -> threshold")
+    thresholds = {str(k): float(v) for k, v in raw_thresholds.items()}
+
+    splits = [
+        ("train", kfold_run_id, "kfold_split/kfold_tiles.parquet", False),
+        ("test", filter_tiles_run_id, "filter_tiles/test_tiles.parquet", True),
+    ]
+
+    with tempfile.TemporaryDirectory() as tmp_root:
+        tmp_root_path = Path(tmp_root)
+        for split_name, src_run_id, src_artifact_path, derive in splits:
+            stats = process_split(
+                split_name=split_name,
+                src_run_id=src_run_id,
+                src_artifact_path=src_artifact_path,
+                embedding_run_id=embedding_run_id,
+                tissue_prop_min=tissue_prop_min,
+                thresholds=thresholds,
+                output_split_dir=tmp_root_path / split_name,
+                derive=derive,
+            )
+            for key, value in stats.items():
+                mlflow.log_metric(f"{split_name}_{key}", value)
+
+        mlflow.log_artifacts(str(tmp_root_path), config.mlflow_artifact_path)
+
+
+if __name__ == "__main__":
+    main()
diff --git a/scripts/submit_embedding_dataset.py b/scripts/submit_embedding_dataset.py
new file mode 100644
index 0000000..23977df
--- /dev/null
+++ b/scripts/submit_embedding_dataset.py
@@ -0,0 +1,18 @@
+from kube_jobs import storage, submit_job
+
+
+submit_job(
+    job_name="tissue-classification-embedding-dataset",
+    username=...,
+    cpu=8,
+    memory="64Gi",
+    gpu=None,
+    public=False,
+    script=[
+        "git clone https://github.com/RationAI/tissue-classification.git workdir",
+        "cd workdir",
+        "uv sync",
+        "uv run python -m preprocessing.embedding_dataset +experiment=...",
+    ],
+    storage=[storage.secure.PROJECTS],
+)
diff --git a/split/kfold_split.py b/split/kfold_split.py
index 150961e..a17c299 100644
--- a/split/kfold_split.py
+++ b/split/kfold_split.py
@@ -12,6 +12,8 @@
 from rationai.mlkit.lightning.loggers import MLFlowLogger
 from sklearn.model_selection import StratifiedKFold
 
+from preprocessing._labels import compute_label_and_tissue_prop
+
 
 def derive_labels(
     dataset: Dataset,
@@ -20,10 +22,7 @@ def derive_labels(
     """Derive label, tissue_prop, and slide_id arrays from the dataset."""
 
     def compute(batch: dict[str, Any]) -> dict[str, Any]:
-        roi_df = pd.DataFrame({col: batch[col] for col in roi_cols})
-        tp = roi_df.sum(axis=1).values
-        lbl = roi_df.idxmax(axis=1).str.removeprefix("roi_coverage_").values
-        lbl[tp == 0] = "background"
+        lbl, tp = compute_label_and_tissue_prop(batch, roi_cols)
         return {"label": lbl.tolist(), "tissue_prop": tp.tolist()}
 
     label_ds = dataset.select_columns(["slide_id", *roi_cols]).map(