A 42-year-old man had swelling in the right side of the neck, cough and chest pain. On admission, an abnormal shadow was detected in the right upper lung field and squamous cell carcinoma of the lung with superior vena cava (SVC) syndrome was diagnosed. Concurrent radiotherapy and systemic chemotherapy consisting of cisplatin and vinorelbine induced a partial response. At 15 months after diagnosis, he was re-admitted because of bilateral pleural effusion and facial edema due to relapse of SVC syndrome. Examination of the milky right pleural effusion revealed chylothorax (959mg/dl of beta-lipoprotein and 675mg/dl of triglyceride). The right effusion was finally controlled by pleurodesis with OK-432. Non-traumatic chylothorax is a rare complication of lung cancer.