At a median time of 20 months following high dose melphalan for myeloma, 29 patients relapsed and were treated with induction chemotherapy to maximum response followed by a second course of high dose melphalan. The majority (90%) of patients received 200 mg m-2 with an autologous bone marrow transplant. Sixteen (55%) patients achieved complete remission and 11 (38%) a partial response. The median duration of remission was 17 (4-42) months. The median survival has not been reached, with 50% of patients alive at 58+ months after presentation. The period of neutropenia was similar during both first and second high dose procedures, but the duration of thrombocytopenia was longer in patients receiving melphalan for a second time (median 22 (16-56) days and 41 (18-69) days respectively). There was one treatment-related death due to thrombocytopenic haemorrhage. Repeated administration of high dose melphalan is a feasible approach for patients with relapsed myeloma.