We identified 60 cases of tuberculous peritonitis during the past 12 years at our health care center. Most of the patients had severe underlying medical conditions, such as cirrhosis, renal failure, diabetes mellitus, and malignancy. Abnormal chest radiograph findings, ascitic fluid lymphocytosis, and biochemical findings for exudates could only identify 33%, 37%, and 53% of the cases, respectively. On the other hand, peritoneal biopsy allowed early definitive diagnosis for 9 patients. Thirty-one patients died, 26 of whom died < or =6 weeks after their initial presentation, often before the result of mycobacterial culture was available. Only 8 patients died of advanced disease after antituberculous therapy was started. Univariate analysis showed that advanced age, underlying diagnosis, and delayed initiation of therapy were associated with higher mortality rates. Standard antituberculous chemotherapy is highly effective. However, conventional microbiologic diagnostic methods are slow and not sensitive enough for establishing a diagnosis of tuberculous peritonitis.