Regulatory impact assessment (RIA) involves a systematic appraisal of the costs and benefits associated with a proposed new regulation and evaluation of the performance of existing regulations. So far, most research has been concerned with the adoption of RIA in OECD countries. The purpose of this paper is to assess the co tribution that RIA can make to "better regulation" in developing and transition economies. The results reported in this paper from a survey of RIA use in a sample of developing and transition countries suggest that a growing number of low and middle-income countries are beginning to apply some form of regulatory assessment, but that the methods adopted are partial in their application and are not systematically applied across government. The paper discusses the implications of the findings for capacity building and future research.