Chylothorax is characterized by accumalation of milky fluid called chyle into the plural space. Most common causes of cyhlothorax are trauma or surgery of thoracic duct and malignancies. Among the malignancies lymphoma is responsible approximately 70% of cyhlothorax but other lymphocytic tumors including chronic lymphocytic leukemia (CLL) is rarely reported. A 71 years old man with known CLL, presented with dispnea and pleural effusion and diagnosed cyhlothorax due to leukemic infiltration that confirmed by immuno flow cytometric analyse.