Forty-four children with acute lymphoblastic leukemia (ALL) who had relapsed (N = 43) or had refractory disease (N = 1) were intensively treated with combination chemotherapy, had remission bone marrow (BM) harvested and purged in vitro with monoclonal antibodies specific for leukemia-associated antigens, underwent postharvest ablative chemotherapy and radiotherapy and subsequently were infused with their autologous marrow. Of the 44 patients treated between November 1980 and January 1988, 19 relapsed, 10 died of complications, and 15 remained in complete remission for a median of 28.5 months (range, 10+ to 94+). Event-free survival (EFS) (+/- SE) at 5 years after autologous transplantation was 29 +/- 8%. For the 26 patients whose initial remission was greater than 2 years, event-free survival was 51 +/- 10%. These results compare favorably with allogeneic transplantation and chemotherapy trials for patients with relapsed ALL, and provide an alternative transplantation option for children without histocompatible donors.