Benign papillary mesothelioma of the peritoneum is an uncommon lesion that is usually discovered by chance during a surgical procedure. This lesion resembles metastatic carcinoma in gross appearance; therefore, intraoperative diagnosis can be difficult. This report presents a case of benign papillary mesothelioma concurrent with gastric cancer. The tumor was located on the hepatogastric ligament and resembled a metastatic peritoneal implant. A pathological review confirmed the diagnosis to be benign papillary mesothelioma.