The donor glomerular filtration rate (GFR) measured before kidney donation is a strong determinant of recipient graft outcome. No tubular function markers have been identified that can similarly be used in donors to predict recipient outcomes. In the current study we investigated whether the predonation tubular maximum reabsorption capacity of phosphate (TmP-GFR), which may be considered as a functional tubular marker in healthy kidney donors, is associated with recipient GFR at one year after transplantation, a key determinant of long-term outcome. We calculated the predonation TmP-GFR from serum and 24h-urine phosphate and creatinine levels in 165 kidney donors, and recipient 125I-iothalamate GFR and eGFR (CKD-EPI) at 12 months after transplantation. Kidney donors were 51±10 years old, 47% were men, and mean GFR was 118±26 mL/min. The donor TmP-GFR was associated with recipient GFR 12 months after transplantation (GFR 6.0 mL/min lower per 1 mg/dL decrement of TmP-GFR), which persisted after multivariable adjustment for donor age, sex, predonation GFR and blood pressure and other potential confounders. Results were highly similar when eGFR at 12 months was taken as the outcome. Tubular damage markers KIM-1 and NGAL were low and not associated with recipient GFR. A lower donor TmP-GFR before donation, which may be considered to represent a functional measure of tubular phosphate reabsorption capacity, is independently associated with a lower recipient GFR one year after transplantation. These data are the first to link donor tubular phosphate reabsorption with recipient GFR post-transplantation.