diff --git a/lib/OpenLayers/Icon.js b/lib/OpenLayers/Icon.js
index fe0a559db6..91517920a5 100644
--- a/lib/OpenLayers/Icon.js
+++ b/lib/OpenLayers/Icon.js
@@ -34,7 +34,7 @@ OpenLayers.Icon.prototype = {
     */
     initialize: function(url, size, offset, calculateOffset) {
         this.url = url;
-        this.size = size;
+        this.size = (size) ? size : new OpenLayers.Size(20,20);
         this.offset = (offset) ? offset : new OpenLayers.Pixel(0,0);
         this.calculateOffset = calculateOffset;