Sclerosing encapsulating peritonitis (SEP) is a serious complication of long-term continuous ambulatory peritoneal dialysis (CAPD), very likely related to a persisting expression of the transforming growth factor beta1 (TGFbeta1) gene on peritoneal mesothelial cells. We report the case of a 67-year-old uremic woman who developed SEP eight years after being placed on CAPD, complicated by eight episodes of bacterial peritonitis. CAPD was therefore stopped and the patient transferred to hemodialysis. The diagnosis of SEP was confirmed by physical findings (vomiting, abdominal pain with palpable mass, ileus, cachexia) and CT data. The patient was treated with tamoxifen (10 mg/day) for three months, and gradually recovered, a subsequent CT showing a significant reduction of the thickness of peritoneal and intestinal loops. Tamoxifen probably interferes with TGFbeta1 and may be useful in the treatment of this CAPD complication.