Temporary transfer to hemodialysis, as a peritoneal rest, may be a rescue therapy to recover ultrafiltration (UF) in patients who develop peritoneal hyperpermeability as a complication of continuous ambulatory peritoneal dialysis (CAPD). However, peritoneal sclerosis has been reported after peritoneal pause. Since the beginning of our CAPD program in 1985, 12 elective peritoneal pauses have been performed in 11 patients who developed type I ultrafiltration failure (D/P240 creatinine: 0.88 +/- 0.09) after 42 +/- 14 months on CAPD. Eight patients recovered UF and remained on CAPD with standard solutions for 10 +/- 9 months more (minimum: 5 months; maximum: 29 months). Only 3 of those patients were later switched to hemodialysis because of recurring UF failure. One patient remains on CAPD (62 months of follow-up). Four patients failed to respond and were permanently transferred to hemodialysis, without signs of developing encapsulating peritoneal sclerosis. The failed pauses were performed later after the detection of UF failure than were the successful ones (483 +/- 574 days vs. 54 +/- 52 days). In our study, 8 of 12 peritoneal pauses (66.6%) successfully treated type I UF failure and prolonged CAPD retention. If a pause is initiated soon after diagnosis of UF failure, results may improve further. We urge prospective studies to better determine the best and timely therapeutic approach in patients with loss of ultrafiltration.