In this paper we seek to gain an understanding of local epistemology--how Malawians themselves understand the epidemiology of HIV (kachirombo, or ?little wild beast?, from the Chichwa chirombo, for wild beast). We approach this by analyzing occasions when several villagers are trying to diagnose the illness or death of someone they know. What information is considered relevant for concluding that an illness or death was due to AIDS? What sources of information are considered authoritative? On what facts do both rural Malawians and the international research community agree, and where do they disagree? And is it likely that these differences might militate against effective reactions to the epidemic?