Continuous ambulatory peritoneal dialysis (CAPD) is a well established method of treating end stage renal failure, and is commonly used as an alternative to hemodialysis. Several complications have been observed. These include catheter malfunction, abdominal and inguinal hernia, and peritonitis. A relatively frequent complication is swelling of external genitalia, due to bowel fluid passing through a patent processus vaginalis. Special diagnostic procedures are necessary to determine the nature of the abnormality and to guide the surgical correction. We reported two cases of patent processus vaginalis in patient on CAPD proved by radionuclide peritoneal scintiscan using Tc-99 m-tin colloid.