diff --git a/src/showdown.js b/src/showdown.js
index 9fdab9a..088b215 100644
--- a/src/showdown.js
+++ b/src/showdown.js
@@ -1129,8 +1129,9 @@ var _DoAutoLinks = function(text) {
 
 	text = text.replace(/<((https?|ftp|dict):[^'">\s]+)>/gi,"<a href=\"$1\">$1</a>");
 
-  // Twitter: @twitter_username
-  text = text.replace(/\s@([-\w])/gi,"<a href=\"http://twitter.com/$1>$1</a>");
+	// Twitter: @twitter_username
+	text = text.replace(/(?:@(\w{1,15}))/gi,"<a href=\"http://twitter.com/$1\">@$1</a>");
+	
 	
 	// Email addresses: <address@domain.foo>