diff --git a/lib/OpenLayers/Layer/Grid.js b/lib/OpenLayers/Layer/Grid.js
index 7709510d31..5e23c828fb 100644
--- a/lib/OpenLayers/Layer/Grid.js
+++ b/lib/OpenLayers/Layer/Grid.js
@@ -583,18 +583,16 @@ OpenLayers.Layer.Grid = OpenLayers.Class(OpenLayers.Layer.HTTPRequest, {
     getTilesBounds: function() {    
         var bounds = null; 
         
-        if (this.grid.length) {
-            var bottom = this.grid.length - 1;
-            var bottomLeftTile = this.grid[bottom][0];
-    
-            var right = this.grid[0].length - 1; 
-            var topRightTile = this.grid[0][right];
-    
-            bounds = new OpenLayers.Bounds(bottomLeftTile.bounds.left, 
-                                           bottomLeftTile.bounds.bottom,
-                                           topRightTile.bounds.right, 
-                                           topRightTile.bounds.top);
+        var length = this.grid.length;
+        if (length) {
+            var bottomLeftTileBounds = this.grid[length - 1][0].bounds,
+                width = this.grid[0].length * bottomLeftTileBounds.getWidth(),
+                height = this.grid.length * bottomLeftTileBounds.getHeight();
             
+            bounds = new OpenLayers.Bounds(bottomLeftTileBounds.left, 
+                                           bottomLeftTileBounds.bottom,
+                                           bottomLeftTileBounds.left + width, 
+                                           bottomLeftTileBounds.bottom + height);
         }   
         return bounds;
     },