A 24-year-old male patient seropositive for the human immunodeficiency virus with Burkitt's Leukemia was treated successfully with aggressive systemic chemotherapy and central nervous system prophylaxis. He presented with a leukocyte count of 68,9OO/pl with 33% L3 lymphoblasts, massive hepatosplenomegaly, generalized lymphadenopathy, a lactic dehydrogenase level of 9105 IU/l, creatinine level of 5.8 mg/dl, and a uric acid level of 43.5 mg/dl. Hemodialysis, intrathecal methotrexate, hydrocortisone and cytosine arabinoside, and fractionated doses of cyclophosphamide followed by vincristine and doxorubicin were promptly instituted. He received eight subsequent courses of chemotherapy consisting of either methotrexate with leucovorin rescue and high dose, continuous infusion cytosine arabinoside or cyclophosphamide, vincristine, and methotrexate with leucovorin. There was marked hematologic toxicity resulting from this treatment. However, the patient was alive and in complete remission more than 6 years from diagnosis. This paper demonstrated that it is possible to successfully treat a patient who is HIV-1 antibody positive with poor prognosis Burkitt's Leukemia. Further studies need to be undertaken to define the least toxic, most effective therapy for this disease. Cancer 1994; 74:1261-4. Key words: Burkitt's leukemia