Isolated peritoneal tuberculosis is an uncommon extrapulmonary form of presentation of tuberculosis in industrialized countries. In most cases, this disease is the result of reactivation and secondary hematogenous spread of a latent infection. Although the suspected diagnosis is given by clinical manifestations and analysis of ascitic fluid (lymphocytic predominance, albumin gradient between serum and ascitic fluid 1g/dl and adenosine deaminase concentration > or = 39 U/L), microbiologic assessment is required for the definitive diagnosis. Mycobacterium bovis causes tuberculosis in animals. Transmission to humans is rare in developed areas, given that it usually occurs through ingestion of unpasteurized contaminated milk. We present a patient with cirrhosis who developed ascites caused by an exceptional infection in our setting.