diff --git a/README.markdown b/README.markdown
index b298c75..3f53736 100644
--- a/README.markdown
+++ b/README.markdown
@@ -65,7 +65,8 @@ If you need to detect when the WebSocket handshake is complete, you can use the
 If the connection's protocol version supports it, you can call `ws.ping()` to
 send a ping message and wait for the client's response. This method takes a
 message string, and an optional callback that fires when a matching pong message
-is received. If the client does not support ping/pong, this method does nothing.
+is received. It returns `true` iff a ping message was sent. If the client does
+not support ping/pong, this method sends no data and returns `false`.
 
 ```js
 ws.ping('Mic check, one, two', function() {