Ninety-eight patients with AML had marrow harvested and cryopreserved at a median of 6 months (range 1-36 months) after achieving first CR with the intent of performing an ABMT at the first sign of relapse. Thirty-three of the 98 patients have not relapsed and 32 survive at a median of 64 months (range 10-105 months) after marrow storage. Sixty-five of the 98 patients relapsed at a median of 7 months (range 1-53 months) after marrow storage. The survival at 2 and 4 years for the 65 patients who relapsed was 22% and 8% respectively. Sixteen of 24 patients treated initially with chemotherapy were ultimately transplanted and two are surviving 21 and 41 months following ABMT and allogeneic marrow transplant respectively. There were no survivors among the eight patients treated with chemotherapy who were not transplanted. Thirty-eight of the 65 patients who relapsed proceeded directly to ABMT without attempts at remission induction, and eight survive disease-free 15-114 months following ABMT. One of the first 17 patients treated with cyclophosphamide and total body irradiation survives without relapse. The probabilities of relapse-free survival, non-relapse mortality, and relapse for the 17 most recent patients prepared with busulfan-containing regimens were 41%, 39% and 32% respectively. Surviving patients had longer first remissions (p = 0.08) and lower peripheral blood blast counts at the time of transplant (p = 0.02) when compared with patients who died. These data suggest that ABMT in untreated first relapse is a reasonable approach for the treatment of patients with AML who relapse.