The annual survey of the Japanese Society for Dialysis Therapy Renal Data Registry (JRDR) was conducted for 4,508 dialysis facilities at the end of 2021 among which 4,454 facilities (98.8％) responded to the facility survey and 4,251 facilities (94.3％) responded to the patient survey. The number of chronic dialysis patients in Japan continues to increase every year；it has reached 349,700 at the end of 2021 and the prevalence ratio of dialysis patients was 2,786 per million population. The mean age of the prevalent dialysis patients in the patient survey was 69.67 years. Diabetic nephropathy was the most common primary disease of the prevalent dialysis patients (39.6％), followed by chronic glomerulonephritis (24.6％) and nephrosclerosis (12.8％). The number of incident dialysis patients during 2021 was 40,511；it decreased by 233 from 2020. The average age was 71.09 years and diabetic nephropathy (40.2％) was the most common cause in incident dialysis patients. Nephrosclerosis became the second cause followed by glomerulonephritis. As 36,156 patients died in 2021, the crude annual mortality rate was 10.4％. The three major causes of death were heart failure (22.4％), infectious disease (22.0％) and malignancy (8.4％). The patients treated by hemodiafiltration (HDF) have been increasing in number rapidly since 2012. The number has reached 176,601 by the end of 2021, which accounted for 50.5％ of all dialysis patients. The number of peritoneal dialysis (PD) patients was 10,501 in 2021, which has slightly increased since 2017. The combination or hybrid therapy with hemodialysis (HD) or HDF was given to 20.3％ of PD patients. Home HD therapy was conducted in 748 patients at the end of 2021；it decreased by 3 from 2020. Disaster preparedness was investigated in 2021. Clinical data about Coronavirus disease (COVID-19) and malignant diseases, and the history of the past living kidney donation was also investigated together with items collected annually. Results obtained on each condition provide a fundamental information from which more clinically effective practice patterns on these conditions will be developed.