diff --git a/lib/OpenLayers/Layer/Grid.js b/lib/OpenLayers/Layer/Grid.js
index 2ed4b61079..cdb6c42835 100644
--- a/lib/OpenLayers/Layer/Grid.js
+++ b/lib/OpenLayers/Layer/Grid.js
@@ -235,7 +235,7 @@ OpenLayers.Layer.Grid.prototype = Object.extend( new OpenLayers.Layer(), {
         var requestString = "";        
         this.params.SRS = this.map.projection;
         // concat tile params with layer params and convert to string
-        var allParams = Object.extend(params, this.params);
+        var allParams = Object.extend(this.params, params);
         var paramsString = OpenLayers.Util.getParameterString(allParams);
 
         var server = this.url;