diff --git a/lib/OpenLayers/Tile/UTFGrid.js b/lib/OpenLayers/Tile/UTFGrid.js
index 35151dba10..96a603198a 100644
--- a/lib/OpenLayers/Tile/UTFGrid.js
+++ b/lib/OpenLayers/Tile/UTFGrid.js
@@ -110,7 +110,7 @@ OpenLayers.Tile.UTFGrid = OpenLayers.Class(OpenLayers.Tile, {
                         this.isLoading = false;
                         this.events.triggerEvent("loadend");
                         if (response.status === 200) {
-                            this.parseData(response);
+                            this.parseData(response.responseText);
                         }
                     },
                     scope: this
@@ -125,15 +125,18 @@ OpenLayers.Tile.UTFGrid = OpenLayers.Class(OpenLayers.Tile, {
     /**
      * Method: parseJSON
      * Parse the JSON from a request
+     *
+     * Parameters:
+     * str - {String} UTFGrid as a JSON string. 
      * 
      * Returns:
      * {Object} parsed javascript data
      */
-    parseData: function(req) {
+    parseData: function(str) {
         if (!this.format) {
             this.format = new OpenLayers.Format.JSON();
         }
-        this.json = this.format.read(req.responseText);
+        this.json = this.format.read(str);
     },
     
     /**