diff --git a/adminer/file.inc.php b/adminer/file.inc.php
index bad22149..6a137e1b 100644
--- a/adminer/file.inc.php
+++ b/adminer/file.inc.php
@@ -1,5 +1,11 @@
 <?php
+if ($_SERVER["HTTP_IF_MODIFIED_SINCE"]) {
+	header("HTTP/1.1 304 Not Modified");
+	exit;
+}
+
 header("Expires: " . gmdate("D, d M Y H:i:s", time() + 365*24*60*60) . " GMT");
+header("Last-Modified: " . gmdate("D, d M Y H:i:s") . " GMT");
 
 if ($_GET["file"] == "favicon.ico") {
 	header("Content-Type: image/x-icon");