diff --git a/owslib/wmts.py b/owslib/wmts.py
index 6fc6fc274..8d8b968af 100644
--- a/owslib/wmts.py
+++ b/owslib/wmts.py
@@ -639,7 +639,7 @@ def from_elements(link_elements):
                         if tml.tilematrix in tilematrixlimits:
                             msg = ('TileMatrixLimits with tileMatrix "%s" '
                                    'already exists' % tml.tilematrix)
-                            raise KeyError(msg)
+                            warnings.warn(msg, RuntimeWarning)
                         tilematrixlimits[tml.tilematrix] = tml
 
                 links.append(TileMatrixSetLink(uri, tilematrixlimits))