diff --git a/tests/test_client.py b/tests/test_client.py
index 0fd98761..e2750613 100644
--- a/tests/test_client.py
+++ b/tests/test_client.py
@@ -1355,6 +1355,27 @@ def test_controller_rpc_reuses_one_socket(client_setup):
     assert len(mock_controller.caller_identities) == 1, "each request opened its own socket"
 
 
+def test_controller_rpc_raises_when_controller_never_replies():
+    """A lost controller reply must surface as an error, not block the caller forever."""
+    context = zmq.Context()
+    silent_controller = context.socket(zmq.ROUTER)
+    port = silent_controller.bind_to_random_port("tcp://127.0.0.1")
+    controller_info = ZMQServerInfo(
+        role=Role.CONTROLLER, id="silent_controller", ip="127.0.0.1", ports={"request_handle_socket": port}
+    )
+    with patch("transfer_queue.client.TQ_CONTROLLER_SEND_RECV_TIMEOUT", 1):
+        client = TransferQueueClient(client_id="client_timeout", controller_info=controller_info)
+    try:
+        start = time.monotonic()
+        with pytest.raises(RuntimeError, match="Resource temporarily unavailable"):
+            client.get_partition_list()
+        assert time.monotonic() - start < 10
+    finally:
+        client.close()
+        silent_controller.close(linger=0)
+        context.term()
+
+
 # =====================================================
 # Checkpoint Interface Tests
 # =====================================================
diff --git a/transfer_queue/client.py b/transfer_queue/client.py
index 73f458f4..93367243 100644
--- a/transfer_queue/client.py
+++ b/transfer_queue/client.py
@@ -48,6 +48,9 @@
 # Raising it also needs enough file descriptors (``ulimit -n``).
 TQ_CLIENT_ZMQ_MAX_SOCKETS = os.environ.get("TQ_CLIENT_ZMQ_MAX_SOCKETS") or None
 DEFAULT_CLIENT_ZMQ_MAX_SOCKETS = 8192
+# A DEALER drops a reply it can no longer route, so without a bound a lost response blocks
+# the caller forever. Generous: a busy controller is normal, an unanswered request is not.
+TQ_CONTROLLER_SEND_RECV_TIMEOUT = int(os.environ.get("TQ_CONTROLLER_SEND_RECV_TIMEOUT", 200))  # seconds
 
 # Pre-bound decorator for controller socket operations.
 with_controller_socket = with_zmq_socket(
@@ -156,6 +159,7 @@ def __init__(
             self.zmq_context,
             client_id,
             "request_handle_socket",
+            timeout=TQ_CONTROLLER_SEND_RECV_TIMEOUT,
         )
 
         # Backstop for a client that is never closed, so the context and its I/O threads do