Background: Collapsed maxilla in unilateral cleft palate patients results in unilateral cross-bite, tapered maxilla and crowding of the maxillary teeth. Distraction osteogenesis (DO) of collapsed maxilla in cleft palate patients has become the contemporary surgical management of many secondary cleft deformities. Purpose: the aim was to compare between the efficiency of using Transpalatal Distraction Osteogenesis (TPDO) and Hyrax appliance for three dimension correction of maxillary hypoplasia in unilateral cleft palate patients both clinically, radiographicaly and study cast analysis. Patients and methods: This study was comprised eight patients group1 (TPDO); (3) males and (5) females and eight patients group2 (Hyrax); (2) males and (6) females with unilateral maxillary hypoplasia after repair of unilateral cleft lip and palate. The age ranged from 13 to 27 years with a mean of 16.88 years. Patients were assessed clinically regarding: photographic, healing of the soft tissue, pain, and device loosening. Radiographically regarding: PA cephalometric, lateral cephalometric views and C.T scan. Study cast regarding: inter canine, inter premolar, and inter molar distance, palatal depth and width. Finally, the data were collected, tabulated and statistically analyzed. Results: The result of this study shows significant difference in inter canine, inter premolar and inter molar distances, palatal width and depth between the pre and post distraction in group (1) than in group (2).