This paper identifies two related priority research topics in the area of regulatory impact assessment (RIA) which are discussed in the last sections of the paper. These are: development of a methodology for assessing the impact of regulation changes in the developing country context; and application of the methodology to proposals for changing the regulatory framework for financial institutions in developing countries. The other sections of the paper elaborate on the context and purpose of RIA, and on the need for financial sector regulatory change in many developing countries. Section 2 discusses regulation in the context of private sector development and economic growth. Section 3 relates regulation to the goal of sustainable development. Section 4 discusses regulatory impact assessment (RIA), the objectives of RIA, the general principles underlying the approach, and the problems associated with developing an appropriate methodology. Section 5 examines the case of financial sector regulation as an appropriate issue for which to apply to RIA.