['Sclerosing encapsulating peritonitis (SEP) is a clinical syndrome with a high mortality rate and is a serious complication of peritoneal dialysis (PD). Peritoneal sclerosis (PS) is a histological diagnosis. PS is usually observed in the peritoneal specimens of patients with SEP. Avoiding SEP is considered to be extremely important for pediatric patients who may require long-term PD. In this study, the characteristics of patients with PS were investigated to determine when to perform peritoneal biopsies and how long PD can be performed safely.', 'A retrospective single-center study.', "Tokyo Metropolitan Kiyose Children's Hospital.", 'A total of 109 children younger than 16 years have received chronic PD in our unit since 1981. Among these children, 16 patients had been on PD for more than 5 years (mean 7.4+/-2.5 years) from May 1992 to March 1999. Peritoneal biopsies were performed in 14 of the 16 patients, who were divided into two groups based on the histological diagnoses: a PS and a peritoneal fibrosis (PF) group.', 'The 14 patients were on PD for a mean of 7.8+/-2.5 years. There were 8 patients with PS and 6 patients with PF. SEP was observed in 2 patients in the PS group. The risk of PS increased with the duration of PD: 57% (8/14) > 5 years, 80% (4/5) > 8 years, and 100% (3/3) > 10 years. All patients in the PS group showed both peritoneal calcifications on abdominal CT scan and poor ultrafiltration at the time of diagnoses.'] Is long-term peritoneal dialysis a risk factor of sclerosing encapsulating peritonitis for children?