diff --git a/modules/rtmessageadd.php b/modules/rtmessageadd.php
index c75d18518d..49b2e5a3ba 100644
--- a/modules/rtmessageadd.php
+++ b/modules/rtmessageadd.php
@@ -375,7 +375,11 @@
 				$message['destination'] = implode(',', $message['destination']);
 		}
 
-		$message['subject'] = 'Re: '.$reply['subject'];
+		if (preg_match('#^Re: #i', $reply['subject']) === 1) {
+			$message['subject'] = $reply['subject'];
+		} else {
+			$message['subject'] = 'Re: '. $reply['subject'];	
+		}
 		$message['inreplyto'] = $reply['id'];
 		$message['references'] = implode(' ', $reply['references']);