diff --git a/src/selector.js b/src/selector.js
index a250746154..553df98ec4 100644
--- a/src/selector.js
+++ b/src/selector.js
@@ -723,7 +723,9 @@ if ( document.querySelectorAll ) (function(){
 	Sizzle = function(query, context, extra, seed){
 		context = context || document;
 
-		if ( !seed && context.nodeType === 9 ) {
+		// Only use querySelectorAll on non-XML documents
+		// (ID selectors don't work in non-HTML documents)
+		if ( !seed && context.nodeType === 9 && !isXML(context) ) {
 			try {
 				return makeArray( context.querySelectorAll(query), extra );
 			} catch(e){}
diff --git a/test/unit/selector.js b/test/unit/selector.js
index 07671c6bee..a648e33d67 100644
--- a/test/unit/selector.js
+++ b/test/unit/selector.js
@@ -28,8 +28,8 @@ if ( location.protocol != "file:" ) {
 			equals( jQuery("foo_bar", xml).length, 1, "Element Selector with underscore" );
 			equals( jQuery("property[name=prop2]", xml).length, 1, "Attribute selector with name" );
 			equals( jQuery("[name=prop2]", xml).length, 1, "Attribute selector with name" );
-			equals( jQuery("#seite1", xml).length, 1, "Attribute selector with name" );
-			equals( jQuery("component#seite1", xml).length, 1, "Attribute selector with name" );
+			equals( jQuery("#seite1", xml).length, 1, "Attribute selector with ID" );
+			equals( jQuery("component#seite1", xml).length, 1, "Attribute selector with ID" );
 			start();
 		});
 	});