An experimental components analysis of brief HIV risk-reduction counseling based on the information-motivation-behavioral skills (IMB) model was conducted with 432 men and 193 women receiving sexually transmitted infection (STI) clinic services. Following baseline assessments, participants were randomly assigned to 1 of 4 90-min risk-reduction counseling sessions that deconstructed the IMB model within a full factorial design. Participants were followed for 9 months, with STI diagnoses monitored over 12 months. Men who received the full IMB session evidenced relatively greater use of risk-reduction behavioral skills and relatively lower rates of unprotected intercourse over 6-months follow-up and had fewer new STIs. For women, however, the motivational counseling demonstrated the most positive outcomes. Results suggest that brief single-exposure HIV prevention counseling can reduce HIV transmission risks.