Adenosine Deaminase (ADA) estimation is routinely used to rule out Tuberculosis in areas with moderate to high TB prevalence. A high ADA level is a characteristic not only of lymphocytic, but also of neutrophilic effusions. The ADA activity was significantly higher in neutrophil than in lymphocyte-rich effusions. Aim to estimate the ADA levels in effusions of body cavities with various infectious and non- infectious aetiologies and to compare the ADA levels in lymphocytic and neutrophilic effusions of infectious effusions. Two hundred and seventy seven patients with pleural, ascitic, pericardial and synovial effusions were analysed and divided depending upon the etiology. Aspirated fluid was subjected to biochemical tests and adenosine deaminase estimation. Cytological examination of fluids was done and categorized effusions as lymphocytic and neutrophilic effusions. ADA values were compared among lymphocytic and neutrophilic effusions. Total Two hundred and seventy seven fluid samples were analysed and ADA values of lymphocytic effusions and neutrophilic effusions were correlated. In lymphocytic infectious group the range of ADA was 140, and mean ± SD was 45.21 ± 21.425 with median of 42. While in neutrophilic infectious effusions, the range of ADA was163 and mean ± SD was 106.24± 39.704 with median of 100. Adenosine deaminase level in all tuberculous (n=76) samples was above diagnostic cut-off (40 U/L); while in empyema and other bacterial group the ADA values are extremely higher than cut- off value. An extremely high ADA activity should raise suspicion of neutrophilic effusions like empyema or other bacterial effusions