Fifty-one children with acute lymphoblastic leukemia (ALL) in second or subsequent remission after a first remission of at least 24 months underwent purged, autologous bone marrow transplantation (ABMT). Bone marrow was harvested in remission and purged in vitro with monoclonal antibodies specific for leukemia-associated antigens. Ablative chemotherapy included cytarabine, teniposide, and cyclophosphamide followed by total body irradiation. Of the 51 patients treated between November 1980 and June 1991, 5 died of treatment-related complications, 18 relapsed, 1 died of a second tumor at 6.7 years, and 27 remained in continuous complete remission for a median of 39 months (range, 9+ to 124+). Event-free survival (EFS) (+/- SE) at 3 years after ABMT was 53% +/- 7%. Leukemia-free survival (LFS) was 58% +/- 8%. In multivariate analysis, the most significant predictors of EFS were duration of longest pre-ABMT remission and remission duration immediately before ABMT. For LFS, the most significant predictors were cell dose per kilogram of marrow reinfused and duration of longest pre-ABMT remission. We conclude that ABMT for this population is an effective therapy available to the majority of children with relapsed ALL.