Index: wp-includes/feed-functions.php
===================================================================
--- wp-includes/feed-functions.php	(revision 2474)
+++ wp-includes/feed-functions.php	(working copy)
@@ -129,9 +129,9 @@
     foreach ($categories as $category) {
         $category->cat_name = convert_chars($category->cat_name);
         if ('rdf' == $type) {
-            $the_list .= "\n\t<dc:subject>$category->cat_name</dc:subject>";
+            $the_list .= "\n\t\t<dc:subject>$category->cat_name</dc:subject>\n";
         } else {
-            $the_list .= "\n\t<category>$category->cat_name</category>";
+            $the_list .= "\n\t\t<category>$category->cat_name</category>\n";
         }
     }
     echo apply_filters('the_category_rss', $the_list, $type);
@@ -156,4 +156,4 @@
 	}
 }
 
-?>
\ No newline at end of file
+?>