A simple imaging procedure has been devised for patients with peritoneo-venous shunts when ascites reaccumulates and a decision must be made on whether or not to revise the shunt. We recently experienced a patient with reaccumulated ascites in whom obstruction of peritoneo-venous shunt was suspected. 5 mCi of 99mTc-phytate was injected into the peritoneal cavity and imaging of the abdomen was performed 1~30 minutes later. With a proper funtioning shunt, radioactivity in the liver and spleen were easily identifiable in this case. If the shunt is obstructed, tracer activity will remain in the pediotoneal cavity and thus can not be identifiable m the liver or spleen. Conclusively, radionuclide methods might be very useful for evaluation of peritoneo-venous shunt patency.