A 52-year-old dentist with kappa light chain multiple myeloma relapsed 6 months after 180 mg/m2 melphalan and an autograft. A partial remission had been attained after the autograft. Relapse occurred while he was on dexamethasone maintenance therapy. Chemotherapy was not an option due to low blood counts. Thalidomide was administered at relatively high doses (escalated up to 700 mg daily and continued for 4 months). There was a prompt decline in urine protein from 6067 mg/day to 2177 mg/day within a month. The response continued to improve with achievement of near-complete remission within 6 months and a decline in urine protein to 413 mg/day. Subsequently, grade 3 neutropenia and peripheral neuropathy required dose reduction to 200 mg/day. Disease activity parameters continued to improve on the lower dose of thalidomide. Nine months after starting thalidomide, the patient is in near-complete remission, enjoys an excellent quality of life, and has returned to work. We conclude that thalidomide can effectively control myeloma relapsing after high-dose chemotherapy, and may be especially useful in resistant cases or those unable to tolerate further chemotherapy. Bone Marrow Transplantation (2000) 25, 1319-1320.