['AIDS-related lymphoma (ARL) remains a frequent complication of HIV infection. We analyzed the outcome of patients with ARL with respect to the use and efficacy of highly active antiretroviral therapy (HAART) and to potential prognostic factors.', 'This multicenter cohort study included patients with systemic ARL diagnosed between 1990-2001. We evaluated overall survival and the effects of several variables on overall survival using the Kaplan-Meier method and the extended Cox proportional hazards model. Response to HAART was used as a time-dependent variable and was defined as a CD4 cell count increase of >/= 100 x 106 cells/l and/or at least one viral load < 500 copies/ml during the first 2 years following diagnosis of ARL.', 'Among 203 patients with ARL, median overall survival was 9.0 months [95% confidence interval (CI), 7.6-12.4 months]. In the univariate analyses, age < 60 years, no previous AIDS, CD4 cell counts >/= 200 x 106 cells/l, hemoglobin > 11 g/dl, Ann Arbor stages I-II and A, no extranodal lesion, response to HAART, and complete remission showed statistically significant association with prolonged overall survival. In the multivariate Cox model, the only factors independently associated with overall survival were response to HAART [relative hazard (RH), 0.32; 95% CI, 0.16-0.62], complete remission (RH, 0.24; 95% CI, 0.15-0.36), previous AIDS (RH, 1.92; 95%CI, 1.23-3.01) and extranodal involvement (RH, 2.85; 95% CI, 1.47-5.51).'] Does response to highly active antiretroviral therapy strongly predict outcome in patients with AIDS-related lymphoma?