Sexual disturbances develop in some patients treated with highly active antiretroviral therapy (HAART). To evaluate sexual dysfunction and the influence that different antiretrovirals could have on those parameters, we conducted a prospective study in patients with stable clinical condition attending an HIV outpatient clinic. A total of 351 evaluations were performed in 189 HIV-infected men, who were interviewed about symptoms of sexual dysfunction. Sexual hormones as well as other clinical and laboratory parameters were also measured at the time of each evaluation. The mean CD4 count was 451.1 x 10(6) cells/L, and viral load was undetectable in two thirds of the determinations. The prevalence of sexual dysfunction was 19.5% overall, but it was influenced by treatment, particularly (although not exclusively) by protease inhibitors (PIs) (27.1% vs. 3.8% for untreated patients). Sexual dysfunction was not related to hypophyseal or gonadal hormonal values. Although several parameters were associated with sexual dysfunction in the univariate analysis, only antiretroviral treatment was significantly predictive of this disorder in a logistic regression analysis. Sexual dysfunction is common in HIV-infected patients in stable clinical condition receiving HAART, and all antiretroviral drugs, particularly PIs, seem to be related to it. Sexual dysfunction in these patients is not related to hormonal causes.