diff --git a/lib/Cake/Routing/Router.php b/lib/Cake/Routing/Router.php
index 3d252b32e..368a2ceff 100644
--- a/lib/Cake/Routing/Router.php
+++ b/lib/Cake/Routing/Router.php
@@ -1055,7 +1055,7 @@ class Router {
  *    an array of arguments to convert into a query string.
  * @param array $extra Extra querystring parameters.
  * @param bool $escape Whether or not to use escaped &
- * @return array
+ * @return string|null
  */
 	public static function queryString($q, $extra = array(), $escape = false) {
 		if (empty($q) && empty($extra)) {