diff --git a/flag.inc b/flag.inc
index d5ef3f4..0aa6e90 100644
--- a/flag.inc
+++ b/flag.inc
@@ -23,11 +23,6 @@ function flag_flag_definitions() {
       'description' => t("Nodes are a Drupal site's primary content."),
       'handler' => 'flag_node',
     ),
-    'comment' => array(
-      'title' => t('Comments'),
-      'description' => t('Comments are responses to node content.'),
-      'handler' => 'flag_comment',
-    ),
     'user' => array(
       'title' => t('Users'),
       'description' => t('Users who have created accounts on your site.'),
@@ -35,6 +30,14 @@ function flag_flag_definitions() {
     ),
   );
 
+  if (module_exists('comment')) {
+    $definitions['comment'] = array(
+      'title' => t('Comments'),
+      'description' => t('Comments are responses to node content.'),
+      'handler' => 'flag_comment',
+    );
+  }
+
   return $definitions;
 }