We report the clinical experience in 451 patients with HIV related non-Hodgkin's lymphoma (HIV-NHL) observed within the Italian Cooperative Group on AIDS and Tumors (GICAT: Gruppo Italiano Cooperativo AIDS e Tumori), a significant number of them being treated at the Aviano Cancer Center (ACC). High grade histology according to the Working Formulation, stages III-IV and B symptoms were detected in the majority of patients. The median survival was 6 months. Based on the Cox model, three factors appeared to influence survival: advanced stage, treatment received and failure to obtain complete remission (CR). In another study aimed at comparing between chemotherapy with or without G-CSF it was shown that G-CSF significantly reduced white blood cells (WBC) nadir duration, the mean delays between cycles, the mean hospitalization time for toxicity per patient treated, without increasing significantly the overall costs. Furthermore, of 77 GICAT patients treated at the ACC with (group A) or without (group B) long-lasting CR, performance status and the mean CD4+ cell count at time of NHL diagnosis were the only parameters of statistical relevance. Based on our data HIV related NHLs are highly aggressive malignancies which are associated with a poor prognosis per se, and because of the underlying HIV infection. Long-term survivals and possible cures can, nonetheless, be obtained in a subgroup of patients, who have a better performance status and a less advanced immune dysfunction related to HIV infection.