Hello, You can do it: 1) with a mail enable group, in "exchange general" tab->"mail size". BUT it only intends for size of mails send to (and not by) the members of this group. 2)per user. Go to "exchange-general" tab of a AD user object-> "message delivary restrictions ", and choose your send/receive limits. Hope it helps, PS: sorry for bad traduction of the tabs . I have french version of exchange :) Yann