diff --git a/app/Mage.php b/app/Mage.php
index 3a75c48568e..c2b76432a54 100644
--- a/app/Mage.php
+++ b/app/Mage.php
@@ -33,6 +33,8 @@
 if (!empty($_SERVER['MAGE_IS_DEVELOPER_MODE']) || !empty($_ENV['MAGE_IS_DEVELOPER_MODE'])) {
     Mage::setIsDeveloperMode(true);
     ini_set('display_errors', 1);
+    ini_set('error_prepend_string', '<pre>');
+    ini_set('error_append_string', '</pre>');
 }
 
 /**