We presented five cases of Crow-Fukase syndrome. Plasma cell hyperplasia or dyscrasia in bone marrow were recognized in all cases and localized bone lesion was seen in three cases. Thyroid dysfunction was seen in three cases; hyperthyroidism in one case and hypothyroidism in two cases, which was considered to be one of the characteristics though it has seldom been described in this disease. Two of four cases treated with prednisolone had good responses but two cases treated with interferon had no effect.