A 26-year-old woman visited the first hospital due to ascites in August 2003, She had continual abdominal pain diagnosed as Irritable bowel disease after a gastrointestinal and colon fiberscopy was performed. Chest-abdominal CT scan revealed normal chest, massive ascites and swollen ovary. To rule out malignancy, surgical biopsy was performed, which brought no significant findings. We focused on the high value of Adenosin deaminase (ADA) in ascites and strongly suspected tuberculotic peritonitis. Consequently, pathologist confirmed the existence of bacterial bodies stained by acid-fast stain after our consultation. Compared with the poor diagnostic accuracy of surgical biopsy, the value of ADA in ascites has a very high sensitivity and specificity. Considering the high risk of being infertile, to begin diagnostic medication of tuberculotic peritonitis is an acceptable choicefor young women with a high value of ADA in the ascites.