A statistical survey conducted at the end of 2005 covered 3985 medical facilities across Japan, and 3940 facilities (98.87%) responded. The dialysis population in Japan at the end of 2005 was 257,765, which showed an increase of 9599 patients (3.87%) from the end of the previous year. The number of patients per million was 2017.6. The crude death rate for one year (from the end of 2004 to the end of 2005) was 9.5%. The mean age of the patients who began dialysis (in 2005) was 66.2 years, and the mean age of the entire dialysis population was 63.9 years. The primary diseases of the patients who began dialysis were diabetic renal disease (42.0%) and chronic glomerulonephritis (27.3%). The mean (+/-SD) serum ferritin concentration of all the dialysis patients was 191 (+/-329) ng/mL. The percentages of antihypertensive agents administered to the hemodialysis patients were as follows: calcium-channel blocker, 50.3%; angiotensin-converting enzyme inhibitor, 11.5%; and angiotensin II-receptor blocker, 33.9%. Of the peritoneal dialysis patients, 33.4% used automated peritoneal dialysis devices. Moreover, 7.3% of the peritoneal dialysis patients received dialysis treatment only in the daytime, and 15% received the treatment only at night. Icodextrin solution was used by 37.2% of the peritoneal dialysis patients. The average amount of dialysis solution used by the peritoneal dialysis patients was 7.43 (+/-2.52) L/day and the average amount of removal fluid was 0.81 (+/-0.60) L/day. A peritoneal equilibration test was conducted on 67% of the patients, and the mean dialysate to plasma creatinine ratio was 0.65 (+/-0.13). The annual incidence of peritonitis in the peritoneal dialysis patients was 19.7%. Of the 126 040 patients who responded to the inquiry of the therapeutic situation of peritoneal dialysis, 676 (0.7%) had a history of encapsulated peritoneal sclerosis and 66 (0.1%) were treated for encapsulated peritoneal sclerosis. The mean life expectancy of the dialysis population in 2003 was calculated according to sex and age. Results showed that the mean life expectancy of the dialysis population was approximately 40-60% of that of the general population of the same sex and age.