OBJECTIVES: I. Determine the overall and disease-free survival and toxicity associated with busulfan/cyclophosphamide (BU/CTX) plus 131I-labeled BC8 antibody (131I-BC8) followed by an HLA-identical related marrow transplant in patients with acute myelogenous leukemia in first or second remission or untreated first relapse. II. Study factors that may influence the biodistribution of 131I-BC8 in this patient population, including marrow cellularity, the level of antigen expression by leukemic cells (in relapsed patients), and the degree of antigen saturation by antibody. III. Determine the efficacy of BU/CTX in patients in first remission unable to receive radiolabeled antibody, e.g., patients who are HAMA-positive, those not tolerating antibody test infusion, those with unfavorable antibody biodistribution, or those for whom antibody is unavailable.