We assessed the quality of life of 859 patients undergoing dialysis or transplantation, with the goal of ascertaining whether objective and subjective measures of the quality of life were influenced by case mix or treatment. We found that 79.1 per cent of the transplant recipients were able to function at nearly normal levels, as compared with between 47.5 and 59.1 per cent of the patients treated with dialysis (depending on the type). Nearly 75 per cent of the transplant recipients were able to work, as compared with between 24.7 and 59.3 per cent of the patients undergoing dialysis. On three subjective measures (life satisfaction, well-being, and psychological affect) transplant recipients had a higher quality of life than patients on dialysis. Among the patients treated with dialysis, those undergoing treatment at home had the highest quality of life. All quality-of-life differences were found to persist even after the patient case mix had been controlled statistically. Finally, the quality of life of transplant recipients compared well with that of the general population, but despite favorable subjective assessments, patients undergoing dialysis did not work or function at the same level as people in the general population.