Full text can be accessed at http://link.springer.com/article/10.1007%2FBF01254376?LI=trueThe Bahaya constitute the largest single cultural unit in the northwestern Tanzanian region of Kagera and occupy the area where AIDS was first diagnosed in Tanzania in 1983. The locality inhabited by the Bahaya is also the worst affected by AIDS in the country. Seroprevalence surveys conducted in 1987 found seroprevalence among those aged 15-54 to be 32.8% in Bukoba urban district, 9.7% in Bukoba rural and Muleba districts, and 4.6% in Karagwe district. More recent surveys would no doubt found higher prevalences of infection. HIV transmission among adults in Africa is primarily bidirectional and through heterosexual activity between multiple sexual partners. The author considers historical antecedents in the social construction of disease, the cultural dimension of Haya sexuality, and the socioeconomic basis of HIV transmission, and argues that disease is as much a biological fact as it is a social fact. Specifically, he highlights the merit of referring to how past epidemics of sexually transmitted diseases have been handled; notes that the sexual transmission of disease is strongly influenced by socioeconomic forces; and discusses how the situation has been aggravated by political instability in neighboring Uganda. Efforts to modify sexual behavior toward the prevention of AIDS will be successful only if coupled with measures to strengthen the region's economy and redress the effects of war.