OBJECTIVE We aimed to examine the influence of donor age on living-donor kidney transplantation (KTx), particularly with regard to long-term graft survival in young recipients with aged kidney grafts. METHODS Between 1988 and 2012, 287 living-donor KTxs were performed in our center. The recipients were divided into 3 groups according to age in years: under 30 (young), 30-49 (middle-aged), and over 50 (old). The data regarding the influence of kidneys from donors aged over 50 years were retrospectively analyzed. RESULTS Graft survival at 1, 5, 10, and 15 years was 94.7, 94.7, 90.2, and 75.2%, respectively, in young recipients who received grafts from donors aged under 50 years, and 96.4, 91.9, 65.4, and 41.4%, respectively, in young recipients who received grafts from donors aged over 50 years (P = 0.023). In contrast, there were no significant differences regarding graft survival and donor age in the middle-aged and old recipient groups. Multivariate analysis revealed that young recipient and rejection episode were significant predictors of graft loss in transplantation from older donors. Histological examination revealed significant age-related changes in the grafts before transplant and a significant higher rate of glomerular hypertrophy at the 1-month protocol biopsy in young recipients with aged kidney grafts. CONCLUSIONS Kidney grafts from older living donors affected long-term graft survival in young recipients. In addition to the damage from rejection, aged kidney grafts, which have less nephron mass, may have a limited capacity to appropriately respond to increases in physiological or metabolic demands of young recipients, leading to a greater reduction in renal function.