This paper is a comparative analysis of 50 case studies collected during the first phase of the Global Development Network (GDN) Bridging Research and Policy project. Reducing poverty and meeting the Millennium Development Goals will require improved policies around the world. Research is one way for policy-makers and other stakeholders to identify which policies are most effective and how they can best be implemented in different contexts. Yet there remains no systematic understanding of what, when, why and how research feeds into development policy. While there is an extensive literature on the research policy links in OECD countries, there has been much less emphasis on research policy links in developing countries. A better understanding of how research can contribute to pro-poor policies, and systems to put it into practice, could improve development outcomes.