This study was performed to investigate the changes of dento-alveolar relationship in relation to the eruption of in cisors using roentgenocephalometry. The Subjects consisted of 76 females from 4 to 8 years with normal occlusion. The following conclusions were obtained: 1. When maxillary and mandibular permanent central incisors were erupted, maxillary alveolar prognathism was increased, while mandibular alveolar prognathism was not changed. 2. Axial inclination of permanent incisors was greater than that of primary incisors.