Background The purpose of this study was to examine the impact of relationship power on HIV risk behaviour among young Black men who have sex with men (MSM) in the Southern US.Data from 425 Black/African American males aged 18-29 years who reported recent anal intercourse with a male partner were analysed. Five selected measures of relationship power were tested for correlation and association with protected receptive anal intercourse using contingency tables and logistic regression analysis.Acts of 100% protected receptive anal intercourse were common (n=277, 65.2%). Men who reported low barriers to condom negotiation were significantly more likely to report protected acts (P<0.001). Men who reported 100% protected acts were less likely to report financial dependence on male sexual partners and serosorting behaviour (12.0% vs 20.7%, P=0.02; 31.5% vs 49.8%, P<0.001 respectively).Future efforts should further examine the role of relationship power in HIV risk among young Black MSM, including the intersection of individual, dyadic and social-structure risks.