Background: Despite the number of antiretroviral (ARV) drugs available its overlapping resistance limits the efficacy of salvage therapy. We analyzed the efficacy and safety of Lopinavir/r (LPV/r) in patients who have at least 2 previous treatment failures and were LPV/r naive. The salvage regime was chosen based on previous ARV used. Methods: Charts of patients Teceiving or who had received LPV/r as satvage therapy in 3 Brazilian research centers were reviewed. It was performed univariate and multivariate analysis (logistic regression) to detect the variables related to the achievement of V1. below 400cp/ml. Results: 89 patients were followed for a median of 258 days, 80% male, mean age of 38 years (21-63). Bascline values (mean) of VL and CD4 counts were 4.8 log (2.4-4.6) and 219 cells/mm3(4-1124), respectively. Patients had been exposed to ARV for a mean time of 57 months (15-116), 75% (67/89) had ever been treated with dual therapy (2 NRTI) and all patients were Pl-experienced. Excluding LPV/r, 9% of patienis had the new regime with two "never used drugs", 27% had only one and 63% hadn't received any new drug, Eleven patients (8%), followed for a mean of 36 wks were discontinued for lack of efficacy. Ten percent developed an adverse experience. 33 patients (37%) achieved an HIV RNA Tevel below 400cp/ml (median of 69 days after salvage starting). At univariate analysis age, previous ARV cxperience time, previous monotherapy use and previous RTV/SQV experience were predictors of a better responsc (VL. < 400 cp/ml) but only menotherapy, RTV/SQV previous use and the basal VL remained significant at the multivariate analysis. Conclusions: LPV/r was well tolerated and safe in this population. The overall response is comparable to other salvage regimens used under less extensive prior treatment history. We believe that the use of tolerable and potent drugs is essential to achievement of a good response on salvage therapy.