diff --git a/wp-admin/includes/comment.php b/wp-admin/includes/comment.php
index 9096da6308..fa9c8588c2 100644
--- a/wp-admin/includes/comment.php
+++ b/wp-admin/includes/comment.php
@@ -159,7 +159,7 @@ function enqueue_comment_hotkeys_js() {
 		wp_enqueue_script( 'jquery-table-hotkeys' );
 }
 
-if ( is_admin() && ('edit-comments.php' == $pagenow || 'edit.php' == $pagenow) ) {
+if ( is_admin() && isset($pagenow) && ('edit-comments.php' == $pagenow || 'edit.php' == $pagenow) ) {
 	if ( get_option('show_avatars') )
 		add_filter( 'comment_author', 'floated_admin_avatar' );
 }