Tuberculosis is among the commonest causes of pleural effusion in India. Adenosine Deaminase (ADA) level in pleural fluid is chemical biomarker that can be employed as a rapid screening tool for tuberculosis. A prospective study was designed to evaluate the importance of pleural fluid ADA level in the diagnosis of tubercular pleural effusion and differentiating it from other causes of exudative pleural effusion. A total of 232 cases of pleural effusion were evaluated, of which 169 (72.85%) were found to be exudative pleural effusion. There were 76 (45%) cases of TB, 32 (19%) of malignancy and 50 (29.6%) of parapneumonic effusion whereas 11 (6.5%) cases belong to other causes or remained undiagnosed. Median ± SD value of ADAfor tubercular pleural effusion, malignant pleural effusion and parapneumonic effusion were 62.37 ± 22.63, 24.12 ± 10.88, and 34.55 ± 20.45 U/l respectively. Our study showed that 68 of 76 cases (89.5%) of patients with tubercular pleural effusion had ADA ≥ 40 U/l while only 3 (9.3%) out of 32 cases of malignant pleural effusion had ADA ≥ 40 U/l. Pleural fluid ADA ≥ 40 U/L yielded 89.47% sensitivity, 72.04% specificity, positive predictive value was 72.34% and a negative predictive value was 89.33% for diagnosis of TB. Pleural fluid ADAcan be utilized for differentiating TB effusions from those of non-tubercular etiology. Moreover it can obviate the need for pleural biopsy.