Objective To explore the diagnosis and treatment of non traumatic chylothorax in non-Hodgkin's lymphoma (NHL) and to understand the differences in diagnosis and treatment between chylothorax and pseudochylothorax. Methods The patient aged 83 years was confrimed as chylothorax and NHL after lymph node biopsy.We reviewed literatures about chylothorax in NHL to analyse the possible mechanism,its diagnosis and treatment. Results The patient was sufferring from unilateral chylothorax diagnosed as true chylothorax by thoracentesis,and progressed to bilateral chylothorax after 1 year.PET/CT examination showed intrathoracic and right cervical lymph nodes enlargement and an increasing metabolic activity.Cervical lymph node biopsy revealed diffuse large B cell type non-Hodgkin's lymphoma.The patient refused any other treatment except the diet therapy and died after 19 months.We searched 19 cases with NHL chylothorax in associated literatures about the treatments including radiotherapy (6/6 improved),chemotherapy (6/11 improved),thoracic duct ligation (I/1 improved),thoracic duct ligation and drug pleurodesis(1/1 improved). Conclusions PET/CT is useful in finding the hidden clues of chylothorax in NHL.There is no standard mangement for NHL chylothorax and the treatment must be individualized. The overall prognosis of NHL chylothorax is similar to that of non-Hodgkin's lymphoma and the patient needs early diagnosis and general treatment in order to prolong the survival time.