Chylothorax refers to the presence of chyle in the pleural space owing to disruption or obstruction of the thoracic duct or one of its tributaries. We present a case of non-traumatic, idiopathic chylothorax in an 18-year-old man. Lymphoscintigraphy was used to identify the site of leak. We tried the full armamentarium of available non-surgical therapy on him, including a modified diet, chest tube insertion, total parenteral nutrition and octreotide. Yet, despite optimal medical therapy, his effusion continued to persist. He eventually required thoracic duct ligation, which resulted in resolution of the effusion.