Tuberculosis (TB) is one of the most common infectious diseases in developing countries including Nepal. Delay in diagnosis and treatment of tuberculosis results in poor prognosis of the disease. This study was conducted to estimate diagnostic cut off values of Adenosine Deaminase (ADA) in cerebrospinal fluid (CSF) and pleural fluid and to evaluate the sensitivity, specificity, positive and negative predictive values ofADA in pleural fluid and CSF from patients with tuberculous and non-tuberculous disease. A total of 98 body fluid (CSF: 24, Pleural fluid: 74) specimens were received for the estimation of ADA. ADA activity was measured at 37 degrees C by spectrophotometric method of Guisti and Galanti, 1984 at 625nm wavelength. Among the patients enrolled for the study subjects for which CSF were received (n = 24) included 8 tuberculous meningitis (TBM), and 16 non-tubercular meningitis (NTM). Pleural fluid samples (n = 74) were received from 19 pulmonary TB with pleural effusion, 17 PTB without pleural effusion and 37 of non-tuberculous disease patients. CSF ADA activity were (11. 1 +/- 2.03 IU/L) and (5.3 +/- +1.89 IU/L) (p <00001) in TM and non-NTM groups and Pleural fluid ADA activity were (10 +/- 22.18 IU/L) and (23.79 +/- 11.62 IU/L) (p < 0.001) in PTB and non-TB groups respectively. ADA test in body fluids, which is simple, cost-effective and sensitive, specific for the tubercular disease is recommended to perform before forwarding the cumbersome and expensive procedures like culture and PCR for TB diagnosis.