The Cancer and Leukemia Group B (CALGB) study 9222 tested the hypothesis that treatment intensification of acute myeloid leukemia (AML) in first remission with multiple chemotherapy agents is superior to high-dose cytarabine (HiDAC) alone. We enrolled 474 patients younger than 60 years old with untreated de novo AML. Daunorubicin and cytarabine resulted in complete remission (CR) in 342 patients (72%), and 309 of these patients were randomized to receive one of 2 different intensification regimens. The first regimen consisted of 3 courses of HiDAC. The second regimen consisted of one course of HiDAC, a second course with etoposide and cyclophosphamide, and a third course with diaziquone and mitoxantrone. After a median follow-up time of 8.3 years, the median survival for all randomized patients was 2.8 years (95% CI, 1.9-6.8 years). There was no difference in disease-free survival (DFS) between the 2 regimens (P = .66). The median DFS was 1.1 years (95% CI, 0.9-1.7 years) for patients receiving HiDAC and 1.0 year (95% CI, 0.9-1.3 years) for those receiving multiagent chemotherapy. Cytogenetics was the only pretreatment characteristic prognostic for DFS, but there was no evidence of a differential treatment effect within cytogenetic risk groups. Toxicity was greater with multiagent chemotherapy. These 2 postremission regimens produced similar outcomes.