|Background: Idiopathic focal segmental glomerulosclerosis (FSGS) occurred at young age is known to predispose poor graft outcome, but our understanding of this predisposition in adulthood-onset FSGS (A-FSGS) is limited due to the scarcity of prior investigations. Here, we compared the graft outcomes between kidney transplant recipients with A-FSGS and childhood-onset FSGS (C-FSGS). Methods: Our study included 47 A-FSGS recipients with an age of onset greater than 15 years and 60 C-FSGS recipients with an age of onset less than 15 years. The primary outcome was the occurrence of graft failure and secondary outcomes were acute rejection (AR), chronic allograft nephropathy (CAN), and recurrence. Assessment of the declining renal function was made by calculating the gradient of the slope of reciprocal serum creatinine against time. Results: Forty-six patients were C-FSGS and 47 patients were A-FSGS. A-FSGS patients showed a longer duration from diagnosis to ESRD, but the other baseline characteristics were similar. Cumulative AR free survival was not different between two groups (p=0.402, by Kaplan-Meier method). Cumulative CAN free survival (p=0.723), recurrence free survival (p=0.743), and graft survival (p=0.279) were also similar in two groups. But the worsening of kidney function defined by the gradient of the slope of reciprocal serum creatinine was steep in C-FSGS than in A-FSGS (-0.033 vs. -0.005), indicating more rapid decline of allograft function (p=0.005). The episodes of AR or CAN significantly affected the graft survival (p=0.002 for AR, and p=0.008 for CAN). In A-FSGS, recurrence of underlying disease was associated with poor graft survival (p=0.004), whereas in C-FSGS, the graft survival was not affected by disease recurrence (p=0.811). Conclusion: The graft outcome of FSGS was similar regardless of onset-age. However, heterogeneity of pathogenesis in A-FSGS may have some impact on graft survival by disease recurrence.