The Korean Society of Nephrology (KSN) launched the official end-stage renal disease (ESRD) patient registry in 1985, and an Internet online registry program was opened in 2001 and revised in 2013. The ESRD Registry Committee of KSN has collected data on dialysis therapy in Korea through the online registry program in the KSN Internet website. The status of renal replacement therapy in Korea at the end of 2012 is described in the following. The total number of ESRD patients was 70,211 at the end of 2012, which included 48,531 hemodialysis (HD) patients, 7,552 peritoneal dialysis (PD) patients, and 14,128 functioning kidney transplant (KT) patients. The prevalence of ESRD was 1,353.3 patients per million population (PMP), and the distribution of renal replacement therapy among ESRD patients was as follows: HD, 69.1%; PD, 10.8%; and KT, 20.2%. The number of new ESRD patients in 2012 was 11,742 (HD, 8,811; PD, 923; and KT, 1,738; the incidence rate was 221.1 PMP). The primary causes of ESRD were diabetic nephropathy (50.6%), hypertensive nephrosclerosis (18.5%), and chronic glomerulonephritis (18.1%). The mean urea reduction ratio was 67.9% in male and 74.1% in female HD patients. The mean Kt/V was 1.382 in male and 1.652 in female HD patients. The 5-year survival rates of male and female dialysis patients were 70.6% and 73.5%, respectively.