diff --git a/README.md b/README.md
index a03fa70ef..d9c9582fd 100644
--- a/README.md
+++ b/README.md
@@ -59,7 +59,7 @@ Bug Fixes
 
 * The Static, Kinematic and Dynamic consts that P2.Body uses were incorrect (fixes #563)
 * Sprite.destroy would fail if it had an Arcade Physics body, now added.
-
+* Group.getAt comparison updated (fixes #578)
 
 
 
diff --git a/src/core/Group.js b/src/core/Group.js
index 5de59fe1d..1acdc9747 100644
--- a/src/core/Group.js
+++ b/src/core/Group.js
@@ -258,7 +258,7 @@ Phaser.Group.prototype.addAt = function (child, index) {
 */
 Phaser.Group.prototype.getAt = function (index) {
 
-    if (index < 0 || index > this.children.length)
+    if (index < 0 || index >= this.children.length)
     {
         return -1;
     }