 <p>You could be encounting a similar issue to: <a href="http://stackoverflow.com/questions/1144894/safari-doesnt-set-cookie-but-ie-ff-does">Safari doesn&#39;t set Cookie but IE / FF does</a></p> <p>Try setting the HttpStatusCode to HttpStatusCode.Ok</p> <p>Some browsers will only accept cookies from a certain response code (like 200, 302).</p>