OBJECTIVE: To evaluate the efficacy of an intervention to reduce HIV transmission risk behaviors and sexually transmitted diseases (STDs) and enhance HIV-preventive psychosocial and structural factors among women living with HIV. DESIGN: A randomized controlled trial of 366 women living with HIV in Alabama and Georgia. INTERVENTION: The intervention emphasized gender pride, maintaining current and identifying new network members, HIV transmission knowledge, communication and condom use skills, and healthy relationships. PRIMARY OUTCOME: Unprotected vaginal intercourse. OTHER OUTCOMES: Proportion never used condoms, incident STDs, psychosocial factors, and number of supportive network members. RESULTS: Over the 12-month follow-up, women in the WiLLOW intervention, relative to the comparison, reported fewer episodes of unprotected vaginal intercourse (1.8 vs. 2.5; P = 0.022); were less likely to report never using condoms (odds ratio [OR] = 0.27; P = 0.008); had a lower incidence of bacterial infections (Chlamydia and gonorrhea) (OR = 0.19; P = 0.006); reported greater HIV knowledge and condom use self-efficacy, more network members, fewer beliefs that condoms interfere with sex, and fewer partner-related barriers to condom use; and demonstrated greater skill in using condoms. CONCLUSION: This is the first trial to demonstrate reductions in risky sexual behavior and incident bacterial STDs and to enhance HIV-preventive psychosocial and structural factors among women living with HIV.