Malignant mesothelioma is an uncommon neoplasm arising in body cavities lined by the mesothelium. Immunohistochemical stains are useful for making a diagnosis, but the correct combination of antibodies as should be selected in a comprehensive assessment. A peritoneal origin combined with desmoplastic histology is an extremely rare disease entity. Here, we report a case of the primary peritoneal malignant mesothelioma. A 53-year-old man admitted to the hospital with abdominal distension and pelvic pain. In laparotomy, peritonitis carcinomatosa situation was exposed. Multiple biopsies were taken from omentum, peritoneum and fascia. Calretinin, WT-1, D2-40, keratin 5/6, mesothelin, keratin 7, keratin 20, CD99, CEA, smooth muscle actin, desmin, CD34 and S-100 were negative. With these findings tumor was evaluated as desmoplastic malignant mesothelioma of the peritoneum. Currently, no established standard treatments for malignant peritoneal mesothelioma, but early diagnosis by exploratory laparotomy followed by chemotherapy may have contributed to longer survival for patients.