Seven patients with relapsed acute leukaemia were treated with high-dose melphalan (HDM) followed by the infusion of autologous cryopreserved remission marrow. Toxicity was minimal and all seven patients had a complete response. Four patients are still in unmaintained remission at 14, 13, 10, and 3 months, the first two having received a second course of HDM to consolidate the result. The role of HDM as a form of intensification therapy for patients with acute myeloid leukaemia in first remission should be investigated.