Severe renal failure is a life-threatening complication of multiple myeloma. Aggressive treatment can reverse acute renal failure in many cases but the prognosis for those who require chronic renal replacement therapy is not clear. We have reviewed the treatment of these patients in the Brighton, Dulwich and Guy's Hospitals renal units. Twenty-three patients were treated for a total of 385 months. Over half presented with end-stage renal failure and required dialysis immediately. Fifteen patients died during the study period and actuarial survival was 45 per cent at one year; six have survived for longer than two years. No prognostic features at presentation were identified but those who responded to chemotherapy survived significantly longer than those who did not. Haemodialysis and continuous ambulatory peritoneal dialysis (CAPD) appeared to be equally effective treatments. Complications from dialysis were more common than in patients with renal failure from other causes. Infection in those treated by CAPD was a serious problem and may be exacerbated by aggressive chemotherapy. Maintenance dialysis offers some patients with multiple myeloma long-term survival and should be offered to all patients who are considered to warrant continuing treatment for their underlying disease.