Erectile dysfunction (ED) and hypogonadism are increasingly recognized conditions, however, the prevalence and etiologies of these conditions among HIV-infected men remain unclear. We studied 300 HIV-infected men who completed standardized questionnaires regarding sexual function and hypogonadal symptoms. An early morning testosterone test was performed; patients with a low serum testosterone level (defined by <300 ng/dL), underwent additional blood tests to determine the etiology of the hypogonadism. The participants' mean age was 39 years (range, 19-72); 61% were Caucasian; 24%, African American; 9%, Hispanic; and 5% other. Participants had been HIV-positive for a mean of 9 years (range, 0.5-20) with a mean CD4 count of 522 cells/mm(3) (range, 1-1531). Sixty percent were receiving antiretroviral therapy. ED was reported by 61.4%; of those with ED, 32% did not have a rigid enough erection for penetration, and 46% were unable to sustain an erection for the completion of intercourse. In the multivariate analysis, increasing age (odds ratio [OR] 1.4 for a 5-year increment, p < 0.001) and depression (OR 2.64, p < 0.0001) were associated with ED. A higher current CD4 count was protective (OR 0.80 for each 100 cells/mm(3), p = 0.004). Only 25% of patients with ED had utilized a phosphodiesterase-5-inhibitor for treatment. Seventeen percent of the 300 men were hypogonadal; there was no correlation between hypogonadism and ED. Increasing age and a higher body mass index (BMI) were positively associated with hypogonadism, while smoking was negatively associated (OR 0.44, p = 0.02). All patients with low testosterone had secondary hypogonadism. There was no association between ED or hypogonadism with the current, past, or cumulative use of HIV medications.