Intensive sequential chemotherapy with mitoxantrone, 12 mg/m2/d on days 1 through 3, etoposide, 200 mg/m2/d as a continuous infusion on days 8 through 10, and cytarabine, 500 mg/m2/d as a continuous infusion on days 1 through 3 and 8 through 10 was administered to 72 patients aged less than 60 years with previously treated acute myelogenous leukemia (AML). Forty patients had refractory AML (nonresponse to prior therapy, early first relapse, or multiple relapse) and 32 had late first relapse. Sixty-one percent of patients, with a 95% confidence interval (CI) ranging from 49% to 72%, achieved complete remission (CR), including 45% (CI: 30% to 62%) of refractory patients and 81% (CI: 64% to 93%) of late first relapse patients. Twenty-nine percent of patients (CI: 19% to 41%) did not respond to therapy and 10% (CI: 4% to 19%) died from therapy-related toxicity. Median duration of aplasia was 30 days. Nonhematologic WHO grade 3 or more toxicity included sepsis (57% of patients), vomiting (10%), mucositis (35%), diarrhea (7%), skin rash (6%), and hyperbilirubinemia (11%). Postinduction therapy was attempted in 36 of 44 CR patients: 16 of them received a second course of the same regimen, 7 received maintenance chemotherapy, 4 underwent autologous bone marrow transplantation (BMT), and 9 allogeneic BMT. At a median follow-up of 20 months, 23 of the 44 complete remitters have relapsed, 1 to 14 months after achievement of CR, including 19 of 31 patients not undergoing BMT. Median survival is 7 months with 16% (CI: 4% to 28%) projected survival at 47 months. Median disease-free survival is 6 months with 21% (CI: 3% to 39%) of CR patients projected to remain disease-free at 46 months. Twenty-six percent (CI: 13% to 43%) of the evaluable patients who did not receive transplantation had inversion of CR duration. Among patients younger than 50 years, there was no significant difference in disease-free survival between patients receiving postinduction chemotherapy and those receiving BMT. We conclude that this chemotherapy regimen is highly efficient and could be used as first-line therapy in young patients with AML.