Authors describe an uncommon case of inheritance of Hashimoto's thyroiditis that affected all the members of a family throughout three generations. Authors analyze recent advances about etiopathogenesis of this disease. In a recent paper was demonstrated that antithyroid peroxidase antibodies (anti-TPO) that have a cytotoxic activity are inherited in a dominant autosomic pattern. However only some epitopes of the antigen thyroid peroxidase predispose to the development of this disease. The peculiarity of this paper is that all the members of this family not only have elevated levels of anti-TPO, but are also all affected by disease. The study on the histocompatibility of antigens did not demonstrate significant date. Authors assert that in the pathogenesis of this disease, genetic factors have a relevant role, also if they are not well known yet. The involvement of environmental factors in this case seems to be unlikely: in fact not all the members of this family were born and lived in the same geographic area.