OBJECTIVES: LPV/r SAT may durably suppress HIV and maintain immunologic response in multiple trial settings, but criteria for improved clinical outcomes have not been determined. Our objective was to evaluate LPV/r SAT use and predictors of viral suppression in an urban clinic setting. METHODS: A retrospective, longitudinal cohort study was conducted of all patients ≥18 years old with ≥2 HIV-1 RNA (“viral load”, VL) measurements starting LPV/r SAT from 2003–2007 at a large urban HIV clinic. Exclusion criteria: prospective clinical trial enrollment or missing data. Variables (demographics, baseline plasma VL and CD4, previous HAART, adherence, and missed clinic visits) evaluated by univariate and stepwise logistic regression to determine predictors of virologic suppression (achievement and/or maintenance of VL <50copies/mL). RESULTS:  Ninety-one patients met inclusion criteria (73% male; 54% black, 35% Caucasian, and 11% Hispanic). Mean age was 42.4 years, median CD4 prior to SAT 290 cells/mm3, and median VL 8960 copies/mL. Reasons for SAT (provider and patient perspective): easy regimen (29%), simplification/maintenance (26%), antiretroviral toxicity (21%), and adherence (23%). In patients with ≥6 months follow-up (n=82), 37 were HAART-naïve and 45 had ≥1 previous HAART regimen. Overall, 73% of HAART-naïve and 47% of patients with ≥1 previous HAART regimen achieved/maintained viral suppression.  In univariate analyses, age, adherence, ethnicity, low VL, high CD4, and AIDS status were significant predictors (p<0.05).  Regression analysis indicated age >50 years (OR 5.2 [95% CI, 1.1-18.4]), white ethnicity (OR 2.5 [1.1-8.3]), and no AIDS (OR 3.0 [1.2-12.5]) were independently associated with viral suppression (p<0.05). SAT was stopped in 17/91 patients for viral failure, poor adherence, drug toxicity, or drug cost. CONCLUSIONS: Incidence of viral suppression was similar to prospective controlled trials in HAART-naive patients.  Older patients with no/mild immunosuppression and limited prior antiretroviral experience may be better candidates for LPV/r SAT.  Larger, prospective evaluations are needed.