We report two cases of multiple sclerosis (MS) beginning in a mother and her daughter at 40 years of age. The diagnosis of MS was certain for both patients (Poser et al., 1983). Clinical features, evolution and response to treatment are comparable in both cases. Cerebral and medullar cord MRI and/or CT Scan showed characteristic lesions of demyelination on periventricular white matter, corpus callosum and brainstem.