It is argued that it will take time to assimilate regulatory impact assessment (RIA) into government decision-making in developing countries and progress is likely to be gradual. The problems that RIA seeks to tackle will vary and so will local needs and capacities. There is no one 'best way of doing things' that can be transferred from country to country. We urgently need to extend our knowledge of regulatory practice in developing and transition economies. As we learn more about the problems encountered, we can harness this knowledge to develop a RIA framework that is appropriate for these countries. Although institutional reform, including regulatory capacity building, is inevitably a deeply political act, it is argued that effective development policy requires the promotion of appropriate methods to improve regulatory practice. If RIA is designed according to the principles outlined in this brief, the result should be better regulation and improved developmental outcomes.