There are important disparities between how HIV transmission, prevention, and mitigation are addressed within sub-Saharan Africa (SSA) and how they are understood by the international aid agencies that design and implement interventions to combat AIDS in this region. Contending that local responses to the AIDS epidemic hinge on a religious framework, this dissertation examines the relationship between religion and HIV risk at both the individual and collective levels in the setting of rural Malawi - a religiously diverse country with high levels of both religious participation and HIV prevalence. This dissertation advances the Durkheimian idea that participation in harmful behaviors is reduced in places where particular religions or religious rituals are widely practiced. Specifically, it addresses the associations between religion and (1) HIV prevention, (2) actual HIV status, and (3) perceived obligations to support families affected by AIDS. The relationships are assessed by employing multiple methodologies and data sources including participant observation data from religious services, in-depth interviews with religious leaders and lay people, and large-scale survey data. This dissertation provides the first empirical assessment of what religious leaders in SSA say and do about HIV in their communities and shows that many have assumed an activist role in combating the epidemic. The relevant practices religious leaders engage in include: preaching explicitly about AIDS on a regular basis, privately advising members to use condoms, actively policing the sexual behavior of their members -- visiting those suspected to be at risk of contracting the disease and to confront them about their sexual behavior, and advising divorce as a strategy for HIV prevention in cases where a member is likely to be infected by an unfaithful spouse. By synthesizing insights from demographic studies of contextual effects on sexual behavior with the notion of "moral communities" from the sociology of religion, this dissertation emphasizes the importance of conceptualizing religion as a supra-individual phenomenon with important implications for the health of populations.