The aim of this retrospective study was to evaluate the clinical utility of ascitic fluid ADA in diagnosing tuberculous peritonitis. A total of 298 ascitic fluid specimens including tuberculous peritonitis, TBP (N= 33) and non-tuberculous peritonitis, non-TBP (N=265) were analyzed for ADA activity by ultraviolet spectrophotometry at 628 nm. The median (range) ADA activity in TBP group was 71.2 (6.7-187) U/L and was significantly higher than in non-TBP group (p < 0.05). Using ROC curves, a cut-off value of 22 U/L for the diagnosis of TBP was found to yield the best results; corresponding sensitivity and specificity were 84.8 % and 82.6%, respectively. With this study, we conclude that the value of ADA can be used to differentiate patients with TBP from those with non-TBP.