Oscar, I've put together an ajax call that passes iso8859-1 instead of utf-8. It's not pretty but shows that by doing your own serialize the server sees iso chars instead of utf.
<script type="text/javascript" src="../js/jquery.js"></script> <script type="text/javascript" src="../plugins/debug/jquery.debug-pack.js "></script> <script type="text/javascript"> $(function(){ $.ajax({ url: "/test.cgi", processData: false, data: 'foo='+ escape('Jörn'), success: function(){console.log(arguments)} }) }); </script> hope it helps you.