Chylothorax is a rare condition that results from thoracic duct damage with chyle leakage from the lymphatic system into the pleural space, usually on the right side. It has multiple aetiologies and is usually discovered after it manifests itself as a pleural effusion. Diagnosis involves cholesterol and triglyceride measurement in the pleural fluid. Complications include malnutrition, immunosuppression and respiratory distress. Treatment may be either conservative or aggressive depending on the clinical scenario. In this review, we discuss the aetiology, diagnosis and treatment of chylothorax. English language publications in MEDLINE and references from relevant articles from January 1, 1980 to February 28, 2008 were reviewed. Keywords searched were chylothorax, aetiology, diagnosis and treatment.