From 6/79 until 2/86, 9 patients (median age 39) with Burkitt's lymphoma were treated. Stage D disease was seen in 7 cases, stage C in two and stage A in one. The main symptom was abdominal pain or a rapidly progressing abdominal tumor. Three patients had bone marrow involvement and two had a Burkitt's leukemia. Three had typical chromosomal aberrations. Therapy consisted of a variety of chemotherapy regimens plus additional radiotherapy and/or bulk surgery. Two patients achieved complete remissions (of 6 and 20+ months duration), and 4 partial remissions were obtained. The remaining patients had either progressive, drug resistant disease or died early. One patient is currently alive and in complete remission at 20+ months. A second patient is alive at 20+ months in partial remission with traces of IgM-paraprotein still detectable. The main causes of death were tumor-lysis syndrome (4 patients) and therapy related sepsis with progressive tumor (3 patients). This poor outcome is probably due to a high proportion of high-risk patients and suboptimal therapy for this rapidly proliferating tumor.