A case of asymptomatic 60 years old male diagnosed as Non-Hodgkin's lymphoma (angioimmunoblastic T-cell type) invading thoracic duct leading to chylothorax is presented. Generally, patients with this moderately aggressive lymphoma are adults who exhibit generalized lymphadenopathy, B-symptoms, polyclonal hypergammaglobulinemia, skin rash and various autoimmune phenomena.