This article discusses recent methodological innovations in the area of cost and benefit assessment of government regulation, in both a prospective and retrospective sense. Much of the extant progress is presented on the front of private costs of compliance. Private benefits, social costs, and social benefits remain much less systematically organized and more arduous to quantitatively assess, mostly due to the difficulty of standardizing partial and general equilibrium counterfactuals. We offer a discussion of potential future methodological improvements in cost-benefit analysis.