A patient who had been successfully treated of Hodgkin's disease (nodular sclerotic type) with mediastinal radiotherapy and polychemotherapy, suffered an acute pericarditis immediately after radiotherapy and a complete atrial-ventricular block 14 years later. Five years later she presented refractory hemorrhagic peritonitis. Necropsy study showed a peritoneal mesothelioma (in non radiated area) and diffuse subpericardial fibrosis. Complete A-V block is a very rare late complication of mediastinal radiotherapy and mesotheliomas (almost exclusively in irradiated areas), also. We have not found any reports on other cases of peritoneal mesotheliomas not attributable to radiotherapy as second neoplasia in Hodgkin's disease.