A 53-years-old woman was admitted to our hospital because of pleural effusion. She underwent pleural biopsy and diagnosed as mesothelioma. Right extrapleuralpneumonectomy was performed. We counted asbestos bodies in the resected lung. 443,571 asbestos bodies were counted in 1 gram of dry lung. We thought that she was heavily exposed to asbestos. Since high risk of incidence of mesothelioma is suggested among her fellow worker, special investigation is necessary for asbestos exposure.