OBJECTIVE To evaluate the effect of acute postoperative alcohol withdrawal on survival of vascularized fibular grafts for mandibular reconstruction. DESIGN Retrospective case series of 17 consecutive patients. MAIN OUTCOMES MEASURE Relation between flap survival and alcohol withdrawal. RESULTS Flap survival rate was 25% for patients who experienced delirium tremens and 85% in the other patients. Had all flaps in patients with postoperative alcohol withdrawal survived, the success rate would have been 89%. Flap loss was related to acute alcohol withdrawal (P =.02, chi2 analysis). The relationship between complication rate and alcohol withdrawal was also significant, using the Fisher exact test. CONCLUSIONS Fibular free flap reconstruction of the mandible is clearly cost-effective when it facilitates return to social function and productivity. In our experience, acute alcohol withdrawal in the first 72 hours after surgery is associated with a high incidence of flap loss. Therefore, we believe that patients at significant risk for alcohol withdrawal should undergo detoxification preoperatively. Society's economic return for investing in free flap reconstruction comes from minimizing convalescence and maximizing postoperative patient productivity. This return will not be realized for poorly selected patients. We are looking further into the effects of alcoholism on flap survival rates.