Hyperostosis of the bones of the forearms and lower legs and mild cranial sclerosis were present in five persons in two generations of a South African kindred of mixed ancestry. This disorder, which is clinically innocuous, is inherited as an autosomal dominant trait. Delineation of this disorder to distinguish it from the other inherited sclerosing bone dysplasias permits accurate prognosis and genetic counselling. In view of the unusual anatomical distribution of the abnormalities, the designation "distal osteosclerosis" is proposed for this entity.