The cases of two sisters with extreme bilateral adrenal hypoplasia, verified at necropsy, have been presented. Two other siblings died in infancy with symptoms which make it very likely that they also had adrenal hypoplasia. A review of the medical literature revealed 23 cases in which necropsy had been performed. These included 15 males and 8 females as well as one set of twins and 3 siblings. Although the incidence of reported cases of adrenal hypoplasia is low, the authors suggest that many cases may have been missed in the past. The clinical picture and possible etiology of this condition have been discussed.