Background: Tuberculous pleural effusion is the most common form of the extra pulmonary tuberculosis. Diagnosis of tuberculous pleuritis is difficult because of its nonspecific clinical presentation and insufficient efficiency of traditional diagnostic methods. the authors investigated the use of adenosine deaminase (ADA) in tuberculous pleuritis diagnosis. Methods: Total 88 patients with pleuritis, including 54 patients with Tuberculous pleural effusion and 34 patients with malignant effusion diagnosed between July 2011 and May 2012 were prospective and cross sectional studied. Detailed clinical history, physical examination and relevant investigation of all patients including ADA estimation by Galanti and Giusti method was done using the ROC curve, the authors determined the optimal cutoff for TB pleurisy. Results: There was statistically significant difference (p0,001) between the means of pleural fluid ADA levels among Tuberculous pleural effusion and malignant effusion. The cutoff value for diagnosing TB effusions was or = 31,5 U/L, with a sensitivity of 87 percent and specificity of 100 percent. The positive predictive value (PPV) was 100 percent and the negative predictive value (NPV) was 83 percent. In addition, the area under the ROC curve was 0,984. Conclusion: Pleural fluid total ADA assay is a sensitive and specific test suitable for rapid diagnosis of TB pleurisy.