We studied whether families and physicians decided as patients do, in discontinuation of life-supporting treatment. We did so by comparing 66 competent patients, who themselves decided to stop dialysis to die, and 66 incompetent patients for whom families and physicians decided. We also compared comatose to demented patients and families’ to physician’s decision-making. There was no difference in sex, diagnosis, age, time period, decision maker (family or physician), site of residence, duration or type of dialysis, home or in-center dialysis or survival time after discontinuation. More competent than incompetent patients died at home (p < 0.005). All incompetent patients had emerging complications, but such complications were present in only 40/60 competent patients (p < 0.0005). In the early 1970s the physician initiated the termination of dialysis in all cases of incompetent patients; in the 1980s this had decreased to 48% ( < 0.001). No case was decided by court or hospital committee. There was no difference between comatose or demented incompetent patients, nor was there any important difference between family and physician decision-making. We believe our study indicates that substitute judgement is applied appropriately and that the decision can safely and best be left to families and physicians.