Exudative pleural effusion is a common problem with long list of causes. Methods used in diagnosis include traditional methods asthoracocentesis with chemical, cytological and microbiologicalexamination of the pleural fluid. Recants methods include detection of biological markers as PCR,ADA for T.B, CYFRA in malignant effusion, thoracoscopy andthoracoscospic pleural biopsy and this study aim to spot light on thedifferent methods used in diagnosis of exudative pleural effusion