Tow cases of congenital ectodermal defect in brothers aged 15 and 10 years were pesinted and the literature was reviewed. They had lack of sweating, sparseness of the hard hairs, absence of lanugo hairs, maldevelopment or defect of most of the teeth, etc. They seemed to be angidrotic type associated with a sex-linked reccessive inheritance in their family backgroud.