diff --git a/taskiq_aio_pika/broker.py b/taskiq_aio_pika/broker.py
index 0cc9601..ce44f41 100644
--- a/taskiq_aio_pika/broker.py
+++ b/taskiq_aio_pika/broker.py
@@ -336,7 +336,15 @@ def with_queues(self, *queues: Queue) -> Self:
         """
         Replace existing queues with new ones.
 
-        :param queues: queues to add.
+        Commonly used in worker entry-point factory functions to narrow which
+        queue(s) a specific worker process listens to, while the full broker
+        (with all queues) is still used for publishing via kick().
+
+        Note: this only affects which queues the worker *listens* to.
+        Routing at kick() time is still determined by the ``queue_name`` label
+        on the message (or the single-queue fallback for unlabelled tasks).
+
+        :param queues: queues to listen to.
         :return: self.
         """
         self._task_queues = list(queues)
@@ -372,18 +380,17 @@ async def kick(self, message: BrokerMessage) -> None:
         )
         delay = parse_val(float, message.labels.get("delay"))
 
-        if len(self._task_queues) == 1:
-            routing_key_name = (
-                self._task_queues[0].routing_key or self._task_queues[0].name
-            )
-        else:
-            routing_key_name = (
-                parse_val(
-                    str,
-                    message.labels.get(self._label_for_routing),
-                )
-                or ""
-            )
+        # An explicit routing label always takes precedence, regardless of how
+        # many queues are in _task_queues.  This is important when with_queues()
+        # has been used to narrow the listening scope to a single queue: without
+        # this check the len==1 shortcut below would silently override the label
+        # and route every outgoing message to the worker's own queue.
+        routing_key_from_label = parse_val(
+            str,
+            message.labels.get(self._label_for_routing),
+        )
+        if routing_key_from_label:
+            routing_key_name = routing_key_from_label
             if self._exchange.type == ExchangeType.DIRECT and routing_key_name not in {
                 queue.routing_key or queue.name for queue in self._task_queues
             }:
@@ -391,6 +398,14 @@ async def kick(self, message: BrokerMessage) -> None:
                     f"Routing key '{routing_key_name}' is not valid. "
                     f"Check routing keys and queue names in broker queues.",
                 )
+        elif len(self._task_queues) == 1:
+            # Backward-compatible shortcut: single-queue brokers don't need to
+            # annotate every task with an explicit queue_name label.
+            routing_key_name = (
+                self._task_queues[0].routing_key or self._task_queues[0].name
+            )
+        else:
+            routing_key_name = ""
 
         if delay is None:
             exchange = await self.write_channel.get_exchange(