diff --git a/date_popup/date_popup.module b/date_popup/date_popup.module
index ca292ef..2fb7b23 100644
--- a/date_popup/date_popup.module
+++ b/date_popup/date_popup.module
@@ -508,7 +508,7 @@ function date_popup_validate($element, &$form_state) {
   }
 
   // If the created date is valid, set it.
-  $value = !empty($date) ? $date->format(DATE_FORMAT_DATETIME) : NULL;
+  $value = !empty($date) ? $date->format($element['#date_format']) : NULL;
   form_set_value($element, $value, $form_state);
 }