Background:  Paying and non-paying sex partners (PSW) of female sex workers (FSW) are a recognized bridge population in Uganda’s HIV epidemic but have not been surveyed to date.

Methods:  From June 2008 to April 2009, 935 FSW (sampled through respondent driven sampling), recruited 573 male PSW to the survey. Eligible PSW had to have sex with their recruiter in the last 6 months, were 18 years or older, and resided in Kampala. Audio computer-assisted self-administered interviews covered demographics and HIV-related risk behaviors. Biomarker testing included HIV and other sexually transmitted diseases (STD). Data presented are unweighted estimates.

Results:  Enrolled into this study were 461(84%) paying (median age: 27 years) and 90 (16%) non-paying partners (median age: 27 years). HIV prevalence was 18.1% (paying: 17.9%, non-paying: 21.1%). HIV prevalence increased with age (18 to 24 years: 5.9%, 25+ years: 26.0%, odds ratio [OR] 5.65, 95% confidence interval [CI] 3.08 to 10.42). Factors associated with HIV infection included frequent alcohol use (OR = 2.20, 95%CI 1.19 to 4.09), reporting STD symptoms (OR = 2.28, 95%CI 1.41 to 3.67), testing positive for an STD (1.77, 95%CI 1.05 to 3.00). Not associated with HIV infection was consuming recreational drugs other than alcohol (OR = 0.77, 95%CI 0.49 to 1.22), a history of paying for sex (OR = 0.81, 95%CI 0.46 to 1.42) or selling sex (OR = 1.09, 95%CI 0.69 to 1.73), ever using condoms (OR = 1.00, 95%CI 0.59 to 1.73), an increasing number of sex partners (P =0.84), having anal sex with another man (OR = 1.15, 95%CI 0.51 to 2.57), anal sex with men or women (OR = 0.60, 95%CI 0.33 to 1.07), or agreeing that AIDS treatment availability makes safe sex less important (OR = 0.97, 95%CI 0.62 to 1.50).

Conclusions: Male sex partners of FSW – both paying clients and non-paying partners - are at substantially higher risk for HIV infection than adult men in the general population. STD and alcohol may be contributing factors in the epidemic among PSW.