diff --git a/date.theme b/date.theme
index c4ea352a..9530f7d1 100644
--- a/date.theme
+++ b/date.theme
@@ -119,16 +119,25 @@ function theme_date_display_combination($variables) {

   switch ($options['fromto']) {
     case 'value':
+      if (empty($dates['value'])) {
+        return NULL;
+      }
       $date1 = $dates['value']['formatted'];
       $date2 = $date1;
       break;

     case 'value2':
+      if (empty($dates['value2'])) {
+        return NULL;
+      }
       $date2 = $dates['value2']['formatted'];
       $date1 = $date2;
       break;

     default:
+      if (empty($dates['value']) || empty($dates['value2'])) {
+        return NULL;
+      }
       $date1 = $dates['value']['formatted'];
       $date2 = $dates['value2']['formatted'];
       break;