diff --git a/libs/plugins/modifier.date_format.php b/libs/plugins/modifier.date_format.php
index 9fe49aa8..4f85b030 100644
--- a/libs/plugins/modifier.date_format.php
+++ b/libs/plugins/modifier.date_format.php
@@ -11,7 +11,11 @@
 require_once SMARTY_DIR . $this->plugins_dir . '/shared.make_timestamp.php';
 function smarty_modifier_date_format($string, $format="%b %e, %Y")
 {
-    return strftime($format, smarty_make_timestamp($string));
+	if($string != '') {
+    	return strftime($format, smarty_make_timestamp($string));
+	} else {
+		return;
+	}
 }
 
 /* vim: set expandtab: */
diff --git a/plugins/modifier.date_format.php b/plugins/modifier.date_format.php
index 9fe49aa8..4f85b030 100644
--- a/plugins/modifier.date_format.php
+++ b/plugins/modifier.date_format.php
@@ -11,7 +11,11 @@
 require_once SMARTY_DIR . $this->plugins_dir . '/shared.make_timestamp.php';
 function smarty_modifier_date_format($string, $format="%b %e, %Y")
 {
-    return strftime($format, smarty_make_timestamp($string));
+	if($string != '') {
+    	return strftime($format, smarty_make_timestamp($string));
+	} else {
+		return;
+	}
 }
 
 /* vim: set expandtab: */