To assess the effect of treatment of vaginal infections on vaginal shedding of cell-free human immunodeficiency virus type 1 (HIV-1) and HIV-1-infected cells, HIV-1-seropositive women were examined before and after treatment of Candida vulvovaginitis, Trichomonas vaginitis, and bacterial vaginosis. For Candida (n=98), vaginal HIV-1 RNA decreased from 3.36 to 2.86 log(10) copies/swab (P<.001), as did the prevalence of HIV-1 DNA (36% to 17%; odds ratio [OR], 2.8; 95% confidence interval [CI], 1.3-6.5). For Trichomonas vaginitis (n=55), HIV-1 RNA decreased from 3.67 to 3.05 log(10) copies/swab (P<.001), but the prevalence of HIV-1 DNA remained unchanged (22%-25%; OR, 0.8; 95% CI, 0.3-2.2). For bacterial vaginosis (n=73), neither the shedding of HIV-1 RNA (from 3.11 to 2.90 log(10) copies/swab; P=.14) nor the prevalence of DNA (from 21% to 23%; OR, 0.8; 95% CI, 0.3-2.0) changed. Vaginal HIV-1 decreased 3.2- and 4.2-fold after treating Candida and Trichomonas, respectively. These data suggest that HIV-1 transmission intervention strategies that incorporate diagnosis and treatment of these prevalent infections warrant evaluation.