diff --git a/litellm/caching/azure_blob_cache.py b/litellm/caching/azure_blob_cache.py
index 742932731b3..bfd3da2fcc3 100644
--- a/litellm/caching/azure_blob_cache.py
+++ b/litellm/caching/azure_blob_cache.py
@@ -44,7 +44,7 @@ class AzureBlobCache(BaseCache):
         print_verbose(f"LiteLLM SET Cache - Azure Blob. Key={key}. Value={value}")
         serialized_value: Final = json.dumps(value)
         try:
-            self.container_client.upload_blob(key, serialized_value)
+            self.container_client.upload_blob(key, serialized_value, overwrite=True)
         except Exception as e:
             # NON blocking - notify users Azure Blob is throwing an exception
             print_verbose(f"LiteLLM set_cache() - Got exception from Azure Blob: {e}")
diff --git a/tests/unit/caching/test_azure_blob_cache.py b/tests/unit/caching/test_azure_blob_cache.py
index 63f4681fd06..26c09fdd415 100644
--- a/tests/unit/caching/test_azure_blob_cache.py
+++ b/tests/unit/caching/test_azure_blob_cache.py
@@ -157,10 +157,36 @@ def test_blob_cache_sync_set_cache(mock_azure_dependencies):
 
     # Verify the call was made correctly
     cache.container_client.upload_blob.assert_called_once_with(
-        "sync_test_key", '{"sync_key": "sync_value", "number": 123}'
+        "sync_test_key", '{"sync_key": "sync_value", "number": 123}', overwrite=True
     )
 
 
+def test_blob_cache_sync_set_cache_replaces_an_existing_key(mock_azure_dependencies):
+    """Re-caching a key must replace the blob, as the async path already does.
+
+    `ContainerClient.upload_blob` defaults to `overwrite=False` and raises
+    `ResourceExistsError` for a key that is already present. `set_cache`
+    swallows that, so without `overwrite=True` the entry silently never updates.
+    """
+    from azure.core.exceptions import ResourceExistsError
+
+    cache = AzureBlobCache("https://my-test-host", "test-container")
+
+    existing_keys = {"sync_test_key"}
+
+    def upload_blob(name, data, **kwargs):
+        if name in existing_keys and not kwargs.get("overwrite"):
+            raise ResourceExistsError("The specified blob already exists.")
+        existing_keys.add(name)
+        return MagicMock()
+
+    cache.container_client.upload_blob.side_effect = upload_blob
+
+    cache.set_cache("sync_test_key", {"v": 2})
+
+    assert cache.container_client.upload_blob.call_args.kwargs.get("overwrite") is True
+
+
 def test_blob_cache_sync_get_cache_not_found(mock_azure_dependencies):
     """Test sync get_cache method when blob is not found"""