Using a multicenter, cross-sectional, observation study, the long-term safety, metabolic profile, and viral efficacy of nevirapine (NVP)-based approaches in HIV-1-infected patients treated for at least 2 years were assessed. For 4 months, all consecutive HIV-1-infected patients who had been receiving an NVP-containing regimen for at least 2 years were recruited. A total of 613 patients were included with a median follow-up period of 43 months (IQR: 31-51). At baseline, 24.5% (150 patients) were treatment naive, 41.5% (254 patients) switched for simplification purposes, and 34% (209 patients) were failing HAART. Increases by five times or more in AST/ALT values were observed in fewer than 2% of patients. Only 5.7% of all adverse events reported during the investigation were attributable to NVP. The percentage of patients with normal HDL cholesterol levels rose from 17.7% at baseline to 35.4% at the last visit. At the latest time point available for analysis, 76% of naive and 74% of those who had switched had HIV-1 RNA loads of <50 copies/ml, while 59% of salvage patients achieved this level of viral suppression. Factors associated with viral suppression at the latest visit were adequate adherence (OR: 2.58, 95% CI: 0.85-7.78, p < 0.001), first-line treatment (OR: 3.02, 95% CI: 1.52-6.00, p = 0.002), and baseline CD4 cells >400 cells/μl (OR: 2.34, 95% CI: 1.22-4.47, p = 0.010). Exposure to nevirapine for up to 4 years is safe. Liver toxicity is infrequent and generally mild. HDL cholesterol levels consistently increase over time and viral suppression is maintained. © Mary Ann Liebert, Inc.