Enhanced knowledge about the behavior change process has facilitated the design of communications programs to reduce the risk of HIV transmission and AIDS. A wide variety of health promotion strategies use communication as either an educational or norm-forming strategy. Health communication, social marketing, and structural intervention theories suggest several principles for HIV/AIDS communication campaigns, including realistic goals, behavior substitution rather than elimination, environmental support for behavioral change, cost-effectiveness, program accessibility to the target audience, and attention to legal and sociocultural obstacles to change. The most successful interventions combine all three approaches in the pursuit of complementary goals. In addition, specific strategies must be designed for high-risk groups such as women, young people, injecting drug abusers, and homosexuals. Major challenges in the years ahead include maintaining government commitment to AIDS prevention; ensuring the continued involvement of nongovernmental and community-based organizations in program development, implementation, and evaluation; and forging closer links between interventions in the fields of prevention and care. The research agenda should include communication strategies for those who are socially marginalized and disenfranchised, the discussion of issues related to drugs and sexuality in cultural climates that discourage open discussion of these topics, the promotion of less stigmatizing attitudes toward people with AIDS, involvement of people with AIDS in the design and implementation of communication programs, and ways to link HIV prevention to other health care activities.