Cleft lip and palate patients have maxillary deficiency because of congenital deformity, surgical scar from primary surgery. Transverse maxillary discrepancy was occasionally found in cleft lip and palate patients with maxillary deficiency, and it was characterized by the constricted maxillary arch, posterior crossbite, and crowding of teeth. There are treatment protocols such as rapid palatal expansion(RPE), surgically assisted rapid maxillary expansion(SARME), and transpalatal distraction(TPD) to correct transverse maxillary discrepancy. Rapid palatal expansion is simple and reliable technique for a correction of transverse maxillary discrepancy. There are some controversies on a design of device, selection of tooth-borne expander or bone-borne expander, secondary alveolar bone grafting, stability and relapse of rapid palatal expansion to correct transverse maxillary discrepancy of cleft lip and palate patients. The purpose of this article was to review considerations for using rapid palatal expansion in the reatment of cleft lip and palate patients.