Cleidocranial dysplasia is a rare developmental disease of bone. It is characterized by hypoplasia of the clavicles, delayed closure of frontanelleles, over-retained primary dentition, delayed eruption of the permanent dentition, and multiple supernumerary teeth. This report presents a ten-year-old girl with cleidocranial dysplasia. Upon initial examination, all primary teeth were over-retained and no permanent tooth was erupted. A panoramic radiograph showed neither congenital missing of permanent tooth nor supernumerary tooth. The clinical features, potential causes of lack of eruption, and dental treatment of cleidocranial dysplasia are discussed. (Taiwan J Pediatr Dent 2(4): 126-132, 2002)