The peritoneal mesothelioma (PM) is a rare, benign or malignant, primary tumour, arising from the peritoneal membrane. The most frequent histological form is the mali gnant one with an incidence of 2-2.6 new cases per mil lion per year. The symptomatology is insidious and poses difficult problems in the diagnosis and the treatment. Instrumental diagnostic investigations are useful only in the diagnostic orientation. Only the pathologic examination allows to distinguish a peritoneal carcinomatosis from PM. The prognosis of MPM is pour. An intense multimodal the rapy, combining surgery with CT and RT, increases the sur vival rates in the patients with MPM. It has been proposed that hernia of abdominal wall play a role in the pathogenesis of this tumor. We believe that hypothesis seems unlikely considering the enormous discre pancy between the incidence of hernial pathology and PM.