Chylothorax (chyle in the pleural space) was first described by Bartolet in 1633. Chylothorax is a diagnosis often under-recognized or mistaken as empyema, causing a delay in management. Knowledge of the anatomy of the thoracic duct is important to understanding the causes, diagnoses and management options of chylothoraces. Chylothorax can generally be classified as traumatic (including surgery) or non-traumatic types. Common causes of non-traumatic chylothoraces include lymphoma and other mediastinal lymphadenopathies (especially metastatic malignancies) and lymphatic abnormalities (including LAM). Presence of chylomicrons or high levels of triglyceride in the pleural fluid define a chylothorax. Lymphangiography can potentially identify the leak site. Multidisciplinary therapeutic approach is often necessary and the best treatment depend on the underlying causes.