Maxillary anterior segmental distraction osteogenesis (MASDO) has been the alternative treatment option for mid-facial deficiency. The patient showed unilateral complete cleft lip and palate on left side, and MASDO with rigid external device (RED) was planned to solve mid-facial deficiency and to create new alveolar bone and space. premaxilla was moved forward after MASDO, but it tended to relapse during orthodontic treatment and retention period. The value of U1 to SN decreased after MASDO, but it was recovered by orthodontic treatment. MASDO with RED provided an effective treatment for cleft lip and palate patients, extended the arch length for collapsed premaxilla, and improved lateral profile without velopharyngeal problem.