One of the hurdles that any agency advocating new regulations must face is the requirement that such regulation be justified, so far as possible, using cost/benefit analysis. The proponents of safety case regulation therefore bear the onus of either justifying the new regulatory regime on cost/benefit grounds, or explaining why strict cost/benefit analysis is impossible or inapplicable in the case at hand. The purpose of this discussion paper is to consider the cost/benefit hurdle and to argue that safety case regulation for offshore petroleum production can in fact surmount it.