Aim: The aim of this study was to evaluate and compare the treatment effects and duration of en-masse retraction combined with labial corticotomy and that with palatal corticotomy using miniscrews as source of anchorage. Methods: Twenty adult patients with bimaxillary or maxillary protrusion requiring orthodontic treatment with upper anterior retraction in the extraction space of first premolars were selected. Patients were divided into two groups; labial corticotomy gruop and palatal corticotomy group, each group consisted of 10 subjects. The retraction time was estimated. Cephalometric radiographs were taken before treatment (T1) and after treatment (T2). Results: There was no significant difference in retraction time between labial and palatal corticotomy groups. Radiographic evaluation showed significant maxillary incisor retraction. Conclusion: The use of corticotomy technique from labial side only could be beneficial for adult patients with difficult surgical access from the palatal side.