BACKGROUND: Nationwide studies on the effects of wealth inequality on kidney transplantation are rare, particularly in a country with an expanded National Health Insurance Service and in Asian countries. METHODS: In this nationwide, population-based cohort study, we reviewed the national claims database of Korea in which details of nationwide health insurance are provided. From 2007 to 2015, 9 annual cohorts of end-stage renal disease patients were included. The annual financial statuses were collected and stratified into 5 subgroups in each year: the aided group in which insurance fee was waived and the 4 other groups divided by quartiles of their medical insurance fee. Time trends of incidence proportion of kidney transplantation among end-stage renal disease patients in each year were initially assessed. The risk of graft failure, both including death-censored graft failure and death with a functioning graft, was analyzed as a prognostic outcome within the transplant recipients. RESULTS: Significant disparity in the accessibility of kidney transplantation was present, and it was further widening, particularly from 2009 in which the National Health Insurance Service started to cover desensitized kidney transplantation. Desensitized or preemptive transplantation was less common in the poorest group who were more frequently receiving transplantation after 5 years of dialysis in the latter years. The prognosis of kidney transplantation was significantly worse in the poorer people, and this disparity also worsened during the study period. CONCLUSIONS: Prominent disparity regarding accessibility to and prognosis of kidney transplantation was observed in Korea according to wealth inequality, and this disparity was worsening.