الوصف Background: Tuberculous pleuritis should be considered in any patient with an exudative pleural effusion. In most cases of tuberculous pleural effusion there are no apparent parenchymal lung lesions on chest radiography. Spontaneous or induced sputum specimen examination for acid fast bacilli (AFB) is important for such cases. Parenchymal lesion including focal areas of subpleural cavitation and lymphadenopathy can be visualized with the use of computed tomography, which is not apparent on routine chest radiography. In such cases there is possibility of isolation of tubercle bacilli in sputum which can be indicator of infectiousness. Aim of the Study: To evaluate the role of sputum examination for (AFB) in tuberculous pleural effusion cases as indicator for infectiousness. Subjects and Methods: The present study included 64 Patients proved to have tuberculous pleural effusions, 32 patients with parenchyma