Fifty-one patients with lymphoblastic lymphoma (LBL) treated with one of five successive intensive chemotherapy protocols for acute lymphoblastic leukemia (ALL) since 1971 were reviewed. The patients were divided into leukemic and nonleukemic groups, and their clinical and laboratory parameters compared. The projected 5-year survival rate for all patients treated with the L10/17 protocols was 45% for both leukemic and nonleukemic LBL. The response to treatment was compared with that of 111 patients with ALL and was nearly identical. Poor prognostic factors were age beyond 30, WBC greater than 50,000/microL, failure to achieve a complete response (CR), and a late CR during induction. Leukemia at presentation, T cell surface markers, and the presence of a mediastinal mass did not adversely affect survival. The use of intensive chemotherapy protocols has proven to be a significant advance in the treatment of LBL.