Vietnam’s HIV epidemic is driven by injection drug use but most IDUs are also sexually active. IDUs’ female sexual partners (SPs) may therefore be at high risk for HIV. Sexual transmission from IDUs to SPs is the most likely avenue for HIV to enter the “general population”.  In several provinces with high HIV prevalence among IDUs, HIV prevalence among antenatal women is >1%.  USAID/Health Policy Initiative Vietnam and the Global Fund are supporting HIV prevention interventions for SPs in Hanoi, Ho Chi Minh City, and Dien Bien, with ongoing evaluation.