diff --git a/lib/OpenLayers/Renderer/VML.js b/lib/OpenLayers/Renderer/VML.js
index 01f78dc523..92308640f4 100644
--- a/lib/OpenLayers/Renderer/VML.js
+++ b/lib/OpenLayers/Renderer/VML.js
@@ -224,7 +224,7 @@ OpenLayers.Renderer.VML = OpenLayers.Class(OpenLayers.Renderer.Elements, {
         // stroke 
         if (options.isStroked) { 
             node.setAttribute("strokecolor", style.strokeColor); 
-            node.setAttribute("strokeweight", style.strokeWidth); 
+            node.setAttribute("strokeweight", style.strokeWidth + "px"); 
         } else { 
             node.setAttribute("stroked", "false"); 
         }