Malignant peritoneal mesothelioma is a rare, aggressive neoplasm with a poor prognosis. It simulates a spectrum of conditions and thus poses great difficulty in diagnosis and management. We report a case of malignant peritoneal mesotheolima in a young female whose abdominal CT showed a complex lesion occupying the entire abdominal cavity. This lesion mimicked an ovarian malignancy with peritoneal carcinomatosis.