A total of 107 patients with newly diagnosed acute myeloblastic leukemia (AML) were referred to the ICRF Department of Medical Oncology at St Bartholomew's Hospital between August 1986 and July 1989. Of those referred, 92 (87%) were treated with remission induction chemotherapy comprising: Adriamycin, cytosine arabinoside (ara-C) and 6-thioguanine if aged < 60 years (57 patients) or mitoxantrone (MTN) and ara-C if aged > 60 years (35 patients). Of those treated, 54 (58%) entered complete remission (CR). Recurrent AML developed in 38 out of these 54 patients (70%) of whom 25 aged 19-73 years (median 50 years) subsequently received MTN and ara-C as reinduction therapy. The 19 younger patients (under 60 years old) received MTN at 12 mg/m2, intravenously, daily for 5 days and ara-C at 100 mg/m2, intravenously, twice daily for 7 days. The six older patients received the same ara-C schedule but the dose of MTN was reduced to 10 mg/m2 for 5 days. Second CR was achieved in 16 out of 25 patients (64%) [12/19 (63%) and 4/6 (67%) for patients aged under or over 60 years, respectively]. Eight of the patients in whom second CR was achieved were aged under 50 years and were thus eligible for additional consolidation comprising myeloablative therapy with autologous bone marrow transplantation (ABMT). Four patients actually received the latter treatment: two remain in second CR at 21 and 46 months. Three of the remaining eight patients aged > 50 years in whom second CR was achieved remain in second CR 8 to 43 months later. Censored for myeloablative therapy + ABMT, the overall median duration of second CR was 5 months. Although remissions tended to be short, in younger patients the possibility of proceeding to myeloablative therapy with autologous bone marrow support makes the regimen worthwhile and, even in older patients, it was sometimes possible to achieve prolonged second remissions.