A 51-year-old woman on peritoneal dialysis for chronic renal failure underwent laparotomy for kidney transplant. One month later, painful subcutaneous edema was observed within the abdominal wall especially apparent in the standing position. A peritoneal fistula was suspected. Peritoneal scintigraphy was performed after infusion of Tc-99m sulfur colloid into the peritoneal cavity followed by SPECT/CT. Tracer uptake was observed between the peritoneal cavity and the subcutaneous space suggesting a postsurgical peritoneal fistula. On static images, the origin of the slight uptake was difficult to determine and could be due to the presence of Tc-99m in the peritoneal catheter that projects into this area. SPECT/CT improved detection of a small peritoneal fistulas.