A prominent mandibular angle is considered to be unattractive in Asian countries because it gives the face a square and muscular appearance. Successful correction by angle ostectomy has been reported, but one of the serious complications of angle reduction ostectomy is fracture of the mandibular condyle. If the ostectomy line is misdirected vertically, the condyle may be fractured. The authors experienced two cases of condylar fracture during angle reduction, Case 1 was a pulled-out condylar fracture, where an L-shaped miniplate was then attached by external approach, and intermaxillary fixation (IMF) with arch bar was used on postoperative day 14. With release of the IMF, a systematic approach for a jaw-opening exercise was be gun. On postoperative day 21, the elastics were placed to assist in guiding protrusion of the mandible anteriorly 24 hours a day. After postoperative day 28, it was possible to completely abandon daytime elastic fixation. The exercise was modified to lateral movement. Case 2 was green-stick condylar fracture, with the IMF with arch bar applied on postoperative day 10. After releasing the IMF, the exercise involved the daily use of several tongue blades, and range of motion increased by wedging additional blades until postoperative day 21. More aggressive stretching was continued with 22 blades on postoperative day 28. On the removal of the arch bar, the occlusion was stable and followed by more aggressive stretching and physical therapy. Both cases were successfully restored and had good results. The authors believe the exercise protocols and algorism they used may serve as a standard procedure of treatment in condylar fracture caused by angle ostectomy.