Objective The objective of this study was to assess the outcomes, complications, and incidence of disease recurrence of mandibular osteoradionecrosis (ORN) after resection and microvascular free flap reconstruction. Study Design Case series with chart review. Setting Academic medical center. Subjects And Methods Retrospective patient data review of 40 patients with mandibular ORN who were treated by segmental mandibulectomy and microvascular reconstruction between 1995 and 2009. All patients received radiation therapy for previous head and neck cancer, and 12 of 40 patients received concurrent chemotherapy. All patients failed to respond to conservative management. There were 26 males and 14 females, with a median age of 62 years. Median follow-up was 17.4 months. Results There were no free flap failures. The incidence of wound-related complications was 55 percent. Median time to complication was 10.6 months. Ten (25%) patients developed symptoms of residual or recurrent ORN, with 70 percent of the recurrences arising in unresected condyles that were adjacent to the segmental mandibulectomy. Statistical analysis revealed that current smokers were at reduced risk to develop residual or recurrent ORN. Conclusion This present study confirms that microvascular free flaps are reliable for treatment of advanced mandibular ORN. Nevertheless, there remains a 55 percent incidence of wound-healing complications. The lack of objective clinical criteria to judge the appropriate amount of mandible resection in patients with ORN remains an unresolved issue that resulted in the development of recurrent ORN in 25 percent of patients. Further investigations are needed to better understand the pathophysiology of ORN to prevent postoperative wound complications and disease recurrence.