Abstract: Background: Lung cancer is the second most common type of cancer in men and women. Lung cancer at a certain stage can spread to the lining of the lung cover or pleura with clinical manifestation of pleural effusion. Identification of malignant cells is known through pleural fluid cytology examination. This histology type of malignant cells is very important for clinicians in determining prognosis, and the most effective type of management for lung cancer patients.The common pleural fluid cytology examination is the conventional cytology smear (CSS. Another pleural fluid examination method namely cell block (CB) was tried to evaluate the preparation of pleural effusion, and it was found that according several studies it was considered superior to conventional method.