diff --git a/google/cloud/aiplatform_v1/services/reasoning_engine_execution_service/async_client.py b/google/cloud/aiplatform_v1/services/reasoning_engine_execution_service/async_client.py
index 4d36c2d70d..083291832b 100644
--- a/google/cloud/aiplatform_v1/services/reasoning_engine_execution_service/async_client.py
+++ b/google/cloud/aiplatform_v1/services/reasoning_engine_execution_service/async_client.py
@@ -408,7 +408,7 @@ async def sample_query_reasoning_engine():
         # Done; return the response.
         return response
 
-    def stream_query_reasoning_engine(
+    async def stream_query_reasoning_engine(
         self,
         request: Optional[
             Union[
@@ -541,7 +541,7 @@ async def sample_stream_query_reasoning_engine():
         self._client._validate_universe_domain()
 
         # Send the request.
-        response = rpc(
+        response = await rpc(
             request,
             retry=retry,
             timeout=timeout,
diff --git a/vertexai/agent_engines/_agent_engines.py b/vertexai/agent_engines/_agent_engines.py
index dd4e35269d..9af30d429c 100644
--- a/vertexai/agent_engines/_agent_engines.py
+++ b/vertexai/agent_engines/_agent_engines.py
@@ -1643,14 +1643,14 @@ def _wrap_async_stream_query_operation(
     """
 
     async def _method(self, **kwargs) -> AsyncIterable[Any]:
-        response = self.execution_api_client.stream_query_reasoning_engine(
+        response = await self.execution_async_client.stream_query_reasoning_engine(
             request=aip_types.StreamQueryReasoningEngineRequest(
                 name=self.resource_name,
                 input=kwargs,
                 class_method=method_name,
             ),
         )
-        for chunk in response:
+        async for chunk in response:
             for parsed_json in _utils.yield_parsed_json(chunk):
                 if parsed_json is not None:
                     yield parsed_json