After congenital heart surgery, medically refractory chylous pleural effusion is associated with considerable morbidity and death, particularly in newborns. In this group of patients, researchers reviewed the experience with the diaphragmatic fenestration surgery. Over 2 years, they undertook a retrospective chart assessment of all patients with diaphragmatic fenestrations for chylous effusion at the institution. They did a total of 9 diaphragmatic fenestration procedures on 8 patients with chylous pleural effusions who had failed to respond to medical treatment. Except for one, they carried all operations on the right side. At the surgery, the median age was 4.6 months (range, 3 weeks to 14 months). The average period between major congenital heart surgery and fenestration was 26 days (range, 4-53 days). They performed a single ventricular repair on three individuals. The average time to remove the chest tube following the treatment was four days. Extubation took an average of three days. Within 12 days, all but one of the patients could progress to full feedings without reaccumulation of chylous effusion. The patients did not experience any problems. Over a median follow-up period of 19 months, recurrent effusion did not emerge. After congenital cardiac surgery, diaphragmatic fenestration is an effective and safe method for managing recurrent chylous effusions.