This article describes the application of the transtheoretical model of behavior change to prevention programs for women at risk for or infected with HIV. The focus of these multisite demonstration projects was to increase condom and contraceptive use. The model was operationalized for use in the following two different intervention approaches: facility-based interventions (individual counseling for women in clinics, shelters, and drug treatment centers) and community-level interventions (including production of small media materials, street outreach, and community mobilization). The authors found that interventions derived from a complex theory can be disseminated to frontline providers who have little prior HIV education experience or academic training. They suggest that the transtheoretical model has value for the design and implementation of HIV prevention programs.