Our patient was refered to hospital for a malignant mesthelioma 22 years after the prior diagnosis of a mesothelioma in his brother. Their family history included others cancers. No exposure to asbestos was documented in brother's history. Literature is rich with family mesothelioma reports. Most of them are linked to an occupationnal asbestos exposure. But, some studies suggest that family genetic factors are involved in the development of mesothelioma: (genetically transmitted mesotheliomas in Turkish families in Cappadoce, family clustering of cancers including mesotheliomas, inhibition of tumor suppressor genes (INK4A, p53, Nf2...), a small proportion of mesothelioma among asbestosis exposed workers. Many studies suggest an interaction between genetic and environment. A genetic predisposition could lead to an increased susceptibility to carcinogenic factors.