We reviewed retrospectively the clinical and surgical data from 9 children with postoperative chylothorax secondary to cardiac surgery for congenital heart disease seen over a 3 year period. Mean age was 26 months and 6 patients were female. The procedures performed were 2 Blalock-Taussig shunts, 6 Bidirectional Glenn anastomoses and 1 modified Fontan procedure. Diagnosis of chylothorax was made by classical means. The overall incidence of chylothorax was 0.8%, with the relative incidences being 2.5% for Blalock-Taussig, 2.7% for Fontan, and 11.7% for the Glenn procedures. All patients were initially treated conservatively with chest tube drainage and hypercaloric diet suplemented with medium chain triglycerides. Parenteral nutrition was needed in 2 patients, one because of sepsis and the other because of progressive malnourishment. High output fistulas and long periods of drainage were noted after cavo-pulmonary procedures. Up to 12% weight loss was observed in 6 patients, one patient was successfully treated of pneumonia and another died of Pseudomonas aeruginosa sepsis. Two patients required chemical pleurodesis because of unabated drainage, with the others being successfully treated conservatively. Chylothorax is a common complication after bidirectional Glenn procedures, and is associated with considerable morbidity and mortality. Earlier operative intervention may be required in these patients. Pleurodesis is a simple, safe, and effective procedure to stop chylous flow.