Two patients were given a pericardial-peritoneal window (PPW) using a subxiphoid approach for chylous pericardial effusion. Complete drainage without recurrence was achieved with PPW in a 22-year-old female patient who had recurrent chylopericardium associated with Klippel-Trenaunay syndrome and in an 11-year-old girl with tricuspid atresia who had undergone the Fontan procedure. PPW is a simple, easy-to-learn, safe, and effective procedure. It creates a communication between the pericardial and peritoneal cavities and is applicable in most patients with noninfectious benign pericardial effusion without serious complications and where adequate drainage can be obtained without the need for external draining systems. We describe the technique, its clinical characteristics, and the results of patients undergoing this treatment.