Copyright © 2017 by the American Society of Nephrology. Studies have estimated the average risk of postdonation ESRD for living kidney donors in the United States, but personalized estimation on the basis of donor characteristics remains unavailable. We studied 133,824 living kidney donors from 1987 to 2015, as reported to the Organ Procurement and Transplantation Network, with ESRD ascertainment via Centers for Medicare and Medicaid Services linkage, using Cox regression with late entries. Black race (hazard ratio [HR], 2.96; 95%confidence interval [95% CI], 2.25 to 3.89; P,0.001) andmale sex (HR, 1.88; 95% CI, 1.50 to 2.35; P,0.001) was associated with higher risk of ESRD in donors. Among nonblack donors, older age was associated with greater risk (HR per 10 years, 1.40; 95% CI, 1.23 to 1.59; P,0.001). Among black donors, older age was not significantly associated with risk (HR, 0.88; 95% CI, 0.72 to 1.09; P=0.3). Greater body mass index was associated with higher risk (HR per 5 kg/m2, 1.61; 95% CI, 1.29 to 2.00; P,0.001). Donors who had a first-degree biological relationship to the recipient had increased risk (HR, 1.70; 95% CI, 1.24 to 2.34; P,0.01). C-statistic of the model was 0.71. Predicted 20-year risk of ESRDfor themedian donorwas only 34 cases per 10,000 donors, but1% of donors had predicted risk exceeding 256 cases per 10,000 donors. Risk estimation is critical for appropriate informed consent and varies substantially across living kidney donors. Greater permissiveness may be warranted in older black candidate donors; young black candidates should be evaluated carefully.