Tuberculous peritonitis is a subacute infectious disease involving the peritoneum. Diagnosis of tuberculous peritonitis is challenging due to its insidious nature, non-specific presentation, and limited availability of diagnostic tests. In areas with endemic TB infection, such as Taiwan, when a patient presented with unexplained ascites, TB should be checked for. In this article, we present a case of tuberculous peritonitis and review the associated literature describing its clinical features, diagnosis, and treatment.