diff --git a/wp-admin/includes/ajax-actions.php b/wp-admin/includes/ajax-actions.php
index c39effe75e..7022c470b1 100644
--- a/wp-admin/includes/ajax-actions.php
+++ b/wp-admin/includes/ajax-actions.php
@@ -903,6 +903,7 @@ function wp_ajax_add_menu_item() {
 		);
 		echo walk_nav_menu_tree( $menu_items, 0, (object) $args );
 	}
+	wp_die();
 }
 
 function wp_ajax_add_meta() {