The influence of HAART on the survival of patients with AIDS-related lymphoma (ARL) was evaluated. A retrospective analysis of 73 HIV-1-infected patients with proven ARL diagnosed between 1992 and 2000 was conducted. Patients received uniformly the same chemotherapy regimen according to CD4 cell counts at NHL diagnosis:, patients with CD4 cells below or above 100 cells x 10(6)/liter received CHOP or ACVBP regimens, respectively. Event-free survival (EFS) and survival were estimated by the Kaplan-Meir method and a Cox model was used to evaluate the effect of different variables on survival. At diagnosis of ARL, the median age was 37 years and 22 patients (30%) had prior AIDS-defining events. Median CD4 cell count was 99 x 10(6)/liter. The median follow-up was 60 months. Ann Arbor stage 3-4 was noted in 60 patients (82%) and bone marrow or meningeal involvement was present in 13 (17%) and 12 (16%) patients, respectively. Two groups were identified: group 1 (n = 38) included patients who had never received HAART and group 2 (n = 35) included those who received HAART either before the diagnosis or following ARL. There was no statistical significant differences in lymphoma extensive stage, presence of B symptoms, meningeal involvement, CD4 cell count at diagnosis, prior AIDS events, or chemotherapy regimens between the two groups. Median survival (MS) of the whole cohort of patients was 8 months. Estimated EFS was significantly higher (30 months) in group 2 compared to group 1 (6.1 months) (p = 0.03). In the multivariate Cox model HAART has an independent significant effect on EFS (p = 0.0085). No influence on outcome was found for other variables except for prior AIDS and bone marrow involvement. HAART has significantly improved the survival and EFS in patients with ARL, independently of chemotherapy regimen.