We report a series of 57 adults patients with lymphoblastic lymphoma treated at our Institution between 1975 and 1987. Mediastinal involvement was seen in 74% (42 cases); extranodal involvement (not including bone marrow) in 24% (14 cases); stage IV in 84% (48 patients) and leukemic phase in 19% (11 patients). In 15 cases immunologic studies were performed 14 proved to be of T type and the other one lack both T and B markers. Survival and duration of remission was better when the patients were treated with aggressive chemotherapy that included maintenance and central nervous system prophylaxis. In the multivariable analysis we observed that mediastinal mass, attainment of a complete remission and high levels of lactic dehidrogenase were associated with a worse prognosis. We believe that patients with lymphoblastic lymphoma have an aggressive disease and that the treatment should be more aggressive than in other non-Hodgkin's lymphomas, and include central nervous system prophylaxis.