diff --git a/lib/github/UserApi.js b/lib/github/UserApi.js
index 050d85021e..c8d556c0cd 100644
--- a/lib/github/UserApi.js
+++ b/lib/github/UserApi.js
@@ -41,11 +41,21 @@ sys.inherits(UserApi, AbstractApi);
      */
     this.show = function(username, callback)
     {
-        this.$api.get(
-            'user/show/' + encodeURI(username),
-            null, null,
-            this.$createListener(callback, "user")
-        );
+        if (!callback) {
+            callback = username;
+	        this.$api.get(
+	            'user/show/',
+	            null, null,
+	            this.$createListener(callback, "user")
+	        );
+        }
+        else {
+	        this.$api.get(
+	            'user/show/' + encodeURI(username),
+	            null, null,
+	            this.$createListener(callback, "user")
+	        );
+        }
     };
 
     /**