The purpose of this paper is to identify research needs for all aspects of the research-to-decision making pathway that will help us understand and mitigate the health effects of climate change as well as ensure that we choose the healthiest and most efficient approaches to climate change adaptation. Recognizing the complexity of this issue, an ad hoc Interagency Working Group on Climate Change and Health (IWGCCH) assembled to develop a white paper on relevant federal research and science needs, including research on mitigation and adaptation strategies. Examples of mitigation and adaptation research needs are identified, but a comprehensive discussion of these issues is not included. These research and science needs broadly include basic and applied science, technological innovations and capacities, public health infrastructure, and communication and education. Consideration is also given to the potential structure of a federal climate change and health research agenda and the use of scientific research results for applications and decision making. The purpose of this paper is to identify research critical for understanding the impact of climate change on human health so that we can both mitigate and adapt to the environmental effects of climate change in the healthiest and most efficient ways. Although the group recognizes the global nature of climate changeÕs impacts on human health, the primary focus of this paper is on the situation in the United States