Kidney transplantation using either kidneys from living or nonliving donors is now generally regarded as the primary therapy for most patients with end-stage kidney failure. In 1984, 32% of all kidney transplantations done in the United States involved living donors. Reasons justifying the use of kidneys from living donors are the higher success rate and the inadequate supply of cadaveric kidneys. In addition, with a living donor, it is easier to arrange for kidney transplantation before dialysis therapy needs to be started. An analysis of 2495 donor nephrectomies reported in the literature, and 5698 donor nephrectomies reported from the 12 largest centers that do kidney transplantation with living donors, indicates an approximate incidence of 1 donor death per 1600 nephrectomies. Although long-term follow-up in kidney donors has shown only that mild, nonprogressive proteinuria develops in about 33% and that the frequency of hypertension may increase, we advise that the kidney donor have a careful long-term follow-up and avoid a high protein intake because of its potential to lead to progressive glomerular damage.