Abstract: Objective To evaluate the in fluence of the donor recipient body surface mismatch on renal graft outcome in living donor kidney transplantation(LDKT). Methods In this prospective study, 286 living kidney transplantation donor-recipient pairs were included. All pairs were stratified into two categories by a break-up of donor/recipient body surface area ratio (D/R BSA-ratio)< 0.9 or ≥ 0.9. The impact of D/B BSA-ratio on recipient allograft outcome was assessed. Results Donors in both groups had similar glomerular filtration rate (GFR). The estimated GFR of recipients in D/R BSA-ratio< 0.9 group were significantly lower than those in D/R BSA-ratio ≥ 0.9 group at 1, 3, 6, 12 months post-transplantation (P< 0.001, respectively). The lower D/B BSA-ratio (< 0.9) conferred greater risk for proteinuria(P < 0.01, respectively). Furthermore, the Kaplan-Meier estimates showed a significant association between donor/recipient BSA ratio and risk of allograft function impairment (P< 0.001). The D/R BSA-ratio< 0.9 was independently associated with allograft function impairment in COX regression model (OR:1.25, 95% CI:1.11-1.46; P< 0.01). Conclusion In conclusion, the lower D/R BSA-ratio is associated with graft function impairment after kidney transplantation. The findings suggest that avoiding donor and recipient BSA incompatibility confers an outcome advantage in LDKT.