diff --git a/src/addons/transitions/ReactCSSTransitionGroupChild.js b/src/addons/transitions/ReactCSSTransitionGroupChild.js
index 0f07867505..a61e4ce608 100644
--- a/src/addons/transitions/ReactCSSTransitionGroupChild.js
+++ b/src/addons/transitions/ReactCSSTransitionGroupChild.js
@@ -54,7 +54,7 @@ var ReactCSSTransitionGroupChild = React.createClass({
     var activeClassName = className + '-active';
     var noEventTimeout = null;
 
-    var endListener = function() {
+    var endListener = function(e) {
       if (e.target !== node) {
         return;
       }