diff --git a/inc/pageutils.php b/inc/pageutils.php
index 6471413b692af10ccda6b5476765911a2d911397..243d9ae1d6cd014a2129fdf06114b5299c620f2a 100644
--- a/inc/pageutils.php
+++ b/inc/pageutils.php
@@ -439,7 +439,7 @@ function isVisiblePage($id){
 function http_conditionalRequest($timestamp){
   // A PHP implementation of conditional get, see
   //   http://fishbowl.pastiche.org/archives/001132.html
-  $last_modified = substr(date('r', $timestamp), 0, -5).'GMT';
+  $last_modified = substr(gmdate('r', $timestamp), 0, -5).'GMT';
   $etag = '"'.md5($last_modified).'"';
   // Send the headers
   header("Last-Modified: $last_modified");