Twenty-six patients (median age 33 years) with poor-risk malignancies were treated with high-dose combination chemotherapy associating BCNU-etoposide-cytosine arabinoside and melphalan (BEAM) followed by autologous bone marrow transplantation (ABMT). Twenty-one patients had malignant lymphomas, three, acute lymphoblastic leukemia (ALL), and two, malignant thymomas. Eleven patients (group 1) were not in complete remission (CR) at the time of BEAM, and fifteen patients (group 2) were in CR. Hematological recovery occurred in all patients. The duration of aplasia and the non-hematological toxicities were similar in both groups. Ten of the eleven patients (group 1) evaluable for response achieved CR and one achieved partial remission (PR). Five patients relapsed, and five are in continuous CR with a short follow-up (median 8 months). Among the fifteen patients in CR at the time of BEAM (group 2), four patients relapsed and ten patients are in unmaintained continuous CR with a median follow-up of 15 months (one patient died in CR). The disease-free survival is 53%, with 29% for patients receiving BEAM while in relapse (group 1) and 65% for patients receiving BEAM while in CR (group 2). These data indicate that BEAM followed by ABMT can produce a high antitumor response with an acceptable toxicity in patients with poor-risk malignancies.