A male 17-year-old boy was tranferred from a private hospital for persistent bilateral pleural effusion.The effusion was confirmed　as bilateral chylothorax by chest CT and lymphangiography. Persistent accumulation of the chylothorax was uncontrollable more 1000cc daily ever after pleuroperitoneal shunt operation and thoracoscopic thoracic duct ligation at Rt. side. Chemical pleurodesis with OK 432 into pleural cavity through thoracostomy tube was attempted as 1.5 KE-3 KE diluted in 50ml of normal saline for 3 consecutive days resulted dramatic reduction of the drainage amount. Chemical pleurodesis with OK 432 appeared to be very helpful for management idiopathic bilateral chylothorax.