Within the health policy field, a growing literature is attempting to understand the diverse responses of policy makers to research, and to explain why certain research findings make their way into policy while others are effectively ignored. In this paper we apply a policy analysis framework to the development of cotrimoxazole prophylaxis national policy in Malawi. Arguing that Malawi was one of the early adopters of cotrimoxazole prophylaxis at a national level, we show how the research to policy process was influenced by national healthcare context, the networks of individuals involved, and the nature of the public health evidence itself.