diff --git a/includes/simplenews.admin.inc b/includes/simplenews.admin.inc
index a446211..c670315 100644
--- a/includes/simplenews.admin.inc
+++ b/includes/simplenews.admin.inc
@@ -180,7 +180,7 @@ function simplenews_admin_issues() {
 
     $options[$issue->nid] = array(
       'title' => l($issue->title, 'node/' . $issue->nid),
-      'category' => $issue->tid ? $categories[$issue->tid] : t('- Unassigned -'),
+      'category' => $issue->tid && isset($categories[$issue->tid]) ? $categories[$issue->tid] : t('- Unassigned -'),
       'created' => format_date($issue->created, 'small'),
       'published' => theme('simplenews_status', array('source' => 'published', 'status' => $issue->status)),
       'sent' => $send_status,