Raltegravir (RAL) is an HIV integrase inhibitor characterized by potent antiretroviral activity, few adverse effects, and lack of cross-resistance to other antiretroviral (ARV) agents. RAL is emerging as a component of effective alternative ARV therapy for those who experience therapeutic failure or intolerance to reverse transcriptase inhibitors (NRTI and NNRTI) and ritonavir (RTV)-boosted protease inhibitor (PI) containing regimens. The combination of RAL with atazanavir (ATV) without a concomitant NRTI-based backbone or the inclusion of RTV may provide an alternative strategy for those unable to tolerate these latter ARV agents. In this report the authors present a case series of treatment-experienced patients managed with RAL + ATV given without a boosting dose of RTV. All patients tolerated this regimen over a course of 25 to 82 weeks, and had good virologic and immunologic outcome with a decrease in HIV RNA levels to <50 copies/mL and a mean CD4 count increase of 234 cells/mm(3).