Asbestos-induced mesothelioma is a challenging social problem in many countries, and oxidative stress via iron is closely associated with its carcinogenesis. Mesothelioma is thought to originate from the mesothelial cells that cover the somatic cavity such as pleural, pericardial and peritoneal cavities. They are single layered and so flat that it is extremely difficult to obtain pure mesothelial cells as control samples from experimental animals. Here we describe a novel method to collect mesothelial cells from animals by the use of simple equipments. Surface of the most organs including lung, spleen and liver are covered with a single layer of mesothelial cells. Scraping the surface of those organs with razor blades after snap-freeze in liquid nitrogen satisfactorily confers almost pure population of mesothelial cells. This simple method would be helpful for obtaining mesothelial control samples from animals to elucidate the molecular mechanisms of a variety of mesothelial pathology.