In general, renal transplant recipients of cadaver kidneys fare less well than recipients of living related donor kidneys in regard to incidence of rejection episodes and stability of renal function. Specific renal function measurements of four cadaver recipients surviving a mean of 29 months without experiencing rejection are compared with those of seven well-matched living related donor recipients who have maintained optimal stability of renal function a minimum of one year following transplant. Renal function of the cadaver group compared favorably and in certain instances exceeded that of the living donor group. These data indicate that even without histocompatibility testing, transplantation of cadaver kidneys can occasionally result in a sustained preservation of renal function which closely parallels that seen in well-matched recipients. Excluding chance histocompatibility, the factors related to such therapeutic success are unknown.