At its International Centres Week in October 2000 (ICW2000), the Consultative Group on International Agricultural Research (CGIAR) adopted a new Vision and Strategy. This paper is about Plank 4 of the CGIAR's Vision and Strategy which calls for the adoption, in collaboration with national and regional partners, of a regional approach to research planning, priority setting and implementation. Given the poverty and impact focus of international public goods research, both national agricultural research systems (NARS) and the CGIAR have advantages in pursuing a regional approach as a component of their respective activities. For the NARS in the region, this means seeking advantages at the regional level that they could not derive solely from a national-level approach. For the CGIAR, this means seeking complementary gains that it could not achieve exclusively through a global or ecoregional approach. These mutual advantages open the door for partnerships in regional research between NARS and their regional organizations, and the CGIAR. The paper highlights the advantages as well as risks and limitations of a regional approach to research. Since ICW2000, all regional and sub-regional organizations and CGIAR Centres have taken action to facilitate consultation processes that could eventually lead to the establishment of a regional approach to research for the CGIAR and NARS. The paper notes some emerging lessons, and takes a forward look.