Part of the Gatekeeper Series produced by the Sustainable Agriculture and Rural Livelihoods Programme at IIED, this paper charts the evolution of climate change and development study and shows why the two fields have, until recently, remained largely independent. It argues that neither can ignore the other if they hope to achieve their interdependent goals of climate change mitigation and avoiding human suffering. Having addressed some of the challenges that such integration will bring, the paper highlights some policy recommendations aimed at the principle actors: donors, governments, NGOs and vulnerable communities. One of the reasons that climate change and development studies have remained largely separate is conceptual in nature: the former is a natural science, the latter a social science. Another is the difference in scales, global and long-term for climate science contrasted with local and near-term for development. While the link had been made as early as 1987 in the Brundtland Report, the literature is exceedingly sparse until around ten years ago. Although more on the international agenda now, the paper suggests that most governments of developing countries have yet to adequately incorporate climate change into their development strategies. Among the challenges ahead are integrating climate change and development at a policy level. The IPCC is beginning to shift toward more social-based issues and this should continue with, it is hoped, a focus on sustainable development in its fourth assessment report. Resolving trade-offs may prove difficult, since not all development projects are ‘win-win’ for both development and climate change. As well as encouraging the mainstreaming of climate change adaptation into development policy (with lessons learnt from the challenges faced by the mainstreaming of gender), the following recommendations are provided:• donor agencies must assess the risk to their investments posed by climate change • governments in developing countries must understand and mitigate the risks posed by climate change and implement  their National Adaptation Programmes of Action (NAPAs)• vulnerable communities, together with NGOs, must understand the extent to which they may be vulnerable.