A case of a middle aged woman with weight loss, ascites, and a pleural effusion is presented where a clinical diagnosis of ovarian cancer was made. Her CA 125 was greatly increased at 873 IU/ml and the ascites was a lymphocytic exudate but cytology failed to show malignant cells. Operative biopsy showed numerous noncaseating granulomas in the omentum but no mycobacterial organisms were seen. Empiric antituberculous treatment was started before positive culture results were received and when treatment had ended both the ascites and pleural effusion had resolved and the CA 125 had fallen to 7 IU/ml. Review of published works showed several other examples of tuberculous peritonitis associated with increased CA 125 and the possible cause of raised CA 125 in this condition is discussed.