Lymphangiomatosis is a rare disorder of the lymphatic system that is known to cause chylothorax. Chyloptysis may occur but chylous bronchial cast formation is rare. A case is reported of lymphangiomatosis in a 34 year old woman whose initial manifestation was cough productive of bronchial casts. Two years later the patient developed a chylothorax. Ligation of the thoracic duct through a low thoracotomy was curative.