Worldwide, and in pockets of poverty in the United States, there is growing evidence that poverty is a major contributor to the spread of human immunodeficiency virus infection. Specific socioeconomic forces contributing to the spread of the infection include the status of women, prostitution, drug use in poor populations, the role of prisons, economic factors that disrupt families, and cultural attitudes. A lack of awareness of or an unwillingness to address the social, cultural, and economic forces contributing to the transmission of the human immunodeficiency virus have hampered attempts to stem the epidemic. A "social prevention" strategy is called for in which socioeconomic influences on human immunodeficiency virus transmission can be ameliorated. Practicing physicians should be aware of these forces because they profoundly influence the effectiveness of patient education, prevention, and treatment.