In Africa, HIV infections occur mostly in stable relationships, yet little is known about the determinants of condom use in this context. We examined condom use among 272 coupled HIV clients in Uganda who had just screened for ART eligibility; 128 had an HIV-positive partner, 47 HIV-negative, and 97 a partner with unknown HIV status. Sixty-six percent reported unprotected sex with their partner over the past 6 months (57-70% across the three subgroups). Multiple variables among socioeconomic characteristics, physical health, social support, and psychosocial adjustment were correlated with condom use in bivariate analysis, but in multivariate analysis, condom use self-efficacy was the only predictor of condom use in the total sample and subgroups; church attendance and physical functioning were also predictors among unknown status couples. This analysis reveals high rates of unprotected sex among coupled HIV clients, regardless of partner's HIV status, and suggests multiple targets for prevention.