Between 1980 and 1990, 10 of 12 children with a symptomatic chylothorax after operation for congenital heart disease failed to respond to traditional medical therapy (thoracentesis, tube thoracostomy, low-fat diet). All 10 patients underwent placement of a pleuroperitoneal shunt, with complete resolution of the chylothorax in 9 patients (90%). Cardiac catheterization, performed before placement of the pleuroperitoneal shunt in 5 patients, demonstrated elevated right atrial pressure in all patients (range, 10 to 25 mm Hg). The pleuroperitoneal shunt functioned effectively in 4 patients with moderately elevated right atrial pressures (range, 10 to 16 mm Hg; median, 13.5 mm Hg) but not in 1 patient with a right atrial pressure of 25 mm Hg. Pleuroperitoneal shunting as treatment for chylothorax after operation for congenital heart disease is safe and effective, even in the face of moderate elevations in right atrial pressure.