Hennekam syndrome was defined as a syndrome characterized by a new autosomal recessive, severe lymphedema in legs, face and genitalia with intestinal lymphangiectasia, various face anomalies and severe mental retardation. A 21 years old male patient was examined due to bilateral pleural effusion. There were edema in both legs and eyelids, swelling in the scrotum and operation scar, broad forehead and face, depressed nasal bridge, epicanthal folds and micrognathia in the physical examination. Chylothorax was diagnosed due to level of pleural triglyceride (650 mg/dL). Lymphatic flow delayed in both lower extremities in lymphoscintigraphy. The patient was diagnosed as Hennekam syndrome due to face anomalies, lymphedema, epilepsy, chylothorax and mild mental retardation.