diff --git a/src/offset.js b/src/offset.js
index 6e97358706..62166bc999 100644
--- a/src/offset.js
+++ b/src/offset.js
@@ -63,6 +63,12 @@ jQuery.offset = {
 			options.using.call( elem, props );
 
 		} else {
+			if ( typeof props.top === "number" ) {
+				props.top += "px";
+			}
+			if ( typeof props.left === "number" ) {
+				props.left += "px";
+			}
 			curElem.css( props );
 		}
 	}