Leukemic relapse remains the most frequent reason for treatment failure in patients with acute myeloblastic leukemia (AML) treated with autologous blood stem cell transplantation (ABSCT). The aim of this study was to evaluate the possible role of autologous bone marrow transplant (ABMT) in patients with AML who relapse after ABSCT. Eighteen consecutive patients were enrolled in the study. At ABMT, 17 patients were in untreated relapse and one was in third complete remission (CR). The preparative regimen was BAVC, and consisted of BCNU 800 mg/m2 on day -6, M-AMSA 150 mg/m2/day on days -5 to -3, VP-16 150 mg/m2/day on days -5 to -3 and Ara-C 300 mg/m2/day on days -5 to -3. There were two regimen-related deaths (11%). Thirteen out of 17 patients in untreated relapse before ABMT achieved CR (76%). The cumulative risk of relapse was 58 +/- 13% at 3 years. Seven patients are in CR between 7+ and 53+ months, with a disease-free survival (DFS) probability of 36 +/- 12% at 3 years. The probability of DFS after ABMT was clearly higher in those patients relapsing later than 7 months after the first autograft (52%) than in patients relapsing earlier (20%)(P = 0.02). In a significant proportion of patients, remission duration was clearly longer after ABMT than ABSCT. We conclude that BAVC conditioning followed by ABMT is associated with a low treatment-related toxicity and results in prolonged DFS in a substantial number of AML patients who relapse after ABSCT. Until better therapeutic options become available, ABMT in untreated relapse is a useful alternative in this group of very poor-risk patients.