Malignant peritoneal mesothelioma is a rare aggres-sive tumor of the peritoneum. An increasing number of malignant mesothelioma cases have been reported in recent years. We report here a very rare case of malignant peritoneal mesothelioma with both umbilical hernia and umbilical metastasis which is also called Sister Mary Joseph’s nodule. We performed laparoscopy which showed specific laparoscopic findings, and the pathological findings of the biopsy specimen led to the diagnosis. This case was associated with umbilical her-nia which could be induced by massive ascites. A newly developed abdominal hernia should be noted as a primary symptom of malignant peritoneal mesothelioma, as shown in the present case. An increasing number of malignant mesothelioma cases have been reported in recent years. We report here a very rare case of malignant peritoneal mesothelioma with both umbilical hernia and umbilical metastasis which is also called This performed was umbilical her-nia which could be induced by massive ascites. A newly developed abdominal hernia should be noted as a primary symptom of malignant peritoneal mesothelioma, as shown in the present case.