Alveolar bone graft allows a tooth adjacent to cleft alveolus to erupt. When the cleft is located distal to the lateral incisor, bone graft is performed for the canine; while it is necessary for the lateral incisor if the cleft is located mesial to the lateral incisor. This study was performed to investigate position of the maxillary lateral incisor to the cleft and to decide appropriate timing for alveolar bone graft. Position of the maxillary lateral incisor was valuated for 139 patients who had been diagnosed as cleft alveolus. Congenital missing of the maxillary lateral incisor was noted 40% (n = 55); distal position to the cleft, 46% (n = 64); mesial, 9% (n = 13); mesial and distal, 5% (n = 7). The maxillary lateral incisor was most commonly found distal to the cleft, which indicates the alveolar bone graft needs to be performed for eruption of the lateral incisor.