Yes you can use Acegi instead of Seam security in a Seam application (I have done it - but now I'm using Seam security). I used Acegi because Seam security didn't exist in Seam when I started to use Seam. I will recommend Seam security because it's a lot easier to use in a Seam application :-) BTW: Why do you think Acegi is more powerful? You can use JBoss Rules (can be very complex) in Seam security. View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4127259#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...