BACKGROUND:Human immunodeficiency virus (HIV) has disproportionately affected African Americans. Couple-level interventions may be a promising intervention strategy. METHODS:To determine if a behavioral intervention can reduce HIV/sexually transmitted disease (STD) risk behaviors among African American HIV serodiscordant couples, a cluster randomized controlled trial (Eban) was conducted in Atlanta, Georgia; Los Angeles, California; New York, New York; and Philadelphia, Pennsylvania; with African American HIV serodiscordant heterosexual couples who were eligible if both partners were at least 18 years old and reported unprotected intercourse in the previous 90 days and awareness of each other's serostatus. One thousand seventy participants were enrolled (mean age, 43 years; 40% of male participants were HIV positive). Couples were randomized to 1 of 2 interventions: couple-focused Eban HIV/STD risk-reduction intervention or attention-matched individual-focused health promotion comparison. The primary outcomes were the proportion of condom-protected intercourse acts and cumulative incidence of STDs (chlamydia, gonorrhea, or trichomonas). Data were collected preintervention and postintervention, and at 6- and 12-month follow-ups. RESULTS:Data were analyzed for 535 randomized couples: 260 in the intervention group and 275 in the comparison group; 81.9% were retained at the 12-month follow-up. Generalized estimating equation analyses revealed that the proportion of condom-protected intercourse acts was larger among couples in the intervention group (0.77) than in the comparison group (0.47; risk ratio, 1.24; 95% confidence interval [CI], 1.09 to 1.41; P = .006) when adjusted for the baseline criterion measure. The adjusted percentage of couples using condoms consistently was higher in the intervention group (63%) than in the comparison group (48%; risk ratio, 1.45; 95% CI, 1.24 to 1.70; P < .001). The adjusted mean number of (log)unprotected intercourse acts was lower in the intervention group than in the comparison group (mean difference, -1.52; 95% CI, -2.07 to -0.98; P < .001). The cumulative STD incidence over the 12-month follow-up did not differ between couples in the intervention and comparison groups. The overall HIV seroconversion at the 12-month follow-up was 5 (2 in the intervention group, 3 in the comparison group) of 535 individuals, which translates to 935 per 100,000 population. CONCLUSION:To our knowledge, this is the first randomized controlled intervention trial to report significant reductions in HIV/STD risk behaviors among African American HIV serodiscordant couples. TRIAL REGISTRATION:clinicaltrials.gov Identifier: NCT00644163.