diff --git a/src/flask_socketio/__init__.py b/src/flask_socketio/__init__.py
index ef7b9e61..419f37c5 100644
--- a/src/flask_socketio/__init__.py
+++ b/src/flask_socketio/__init__.py
@@ -910,7 +910,7 @@ def on_join(data):
             username = session['username']
             room = data['room']
             join_room(room)
-            send(username + ' has entered the room.', room=room)
+            send(username + ' has entered the room.', to=room)
 
     :param room: The name of the room to join.
     :param sid: The session id of the client. If not provided, the client is
@@ -935,7 +935,7 @@ def on_leave(data):
             username = session['username']
             room = data['room']
             leave_room(room)
-            send(username + ' has left the room.', room=room)
+            send(username + ' has left the room.', to=room)
 
     :param room: The name of the room to leave.
     :param sid: The session id of the client. If not provided, the client is