Kidney volume has been proven to be a surrogate marker of nephron mass and renal function. We studied 190 donor and recipient pairs undergoing living donor kidney transplantation at our institution during 9years. Different metrics of donor kidney volume (DKV) were explored: alone or indexed to recipient's anthropometry, as body surface area (BSA). DKV/BSA (min. 49.7; P33rd 77.7; P67th 95.3; max. 176cm3 /m2 ) was chosen given its higher correlation with eGFR at 1year, and recipients were divided according to its tertiles (T). The eGFR at 1year was lower in T1, when compared with T2 (P=0.015) and T3 (P<0.001). In a multivariable model, a regression spline revealed that a DKV/BSA lower than 80 was significantly associated with an eGFR at 1year <60. In the first 6years, the overall annual eGFR slope was -0.90ml/min/year. Acute rejection occurred in 19%, 11%, and 0% of patients in T1, T2, and T3, respectively (P<0.001). DKV/BSA increased stepwise from cellular- (n=12) to antibody-mediated (n=7) AR cases and to those without AR (n=171; P=0.002; no AR versus cellular AR). Lower DKV/BSA ratio was associated with significantly worse graft function and higher incidence of AR. Hence, it can be a tool for better selection of donors in order to improve graft outcomes, particularly in the setting of multiple potential living donors or kidney paired exchange programs.