BACKGROUND This retrospective study was intended to determine the incidence and causes of postoperative complications in patients following head and neck reconstruction using microvascular free flaps. METHODS A total of 202 consecutive microvascular free flaps were performed for reconstruction of the head and neck by the same surgeon, 85% of the defects arose following the treatment of malignancies. Flap donor sites included latissimus-dorsi flap (n=83), radial forearm (n=35), fibula (n=31), iliac crest (n=36), TRAM flap (n=3), groin flap (n=l), jejunal flap (n=13). The incidence of postoperative complications and patient-related characteristics (age, sex, diagnosis, comorbidity level, operation duration, defect site, history of radiotherapy/chemotherapy) were retrospectively analyzed. RESULTS Free flaps proved to be extremely reliable, with a 2.9% incidence of free flap failure. Postoperative medical complications occurred in 11.4% of cases, with cardiac, pulmonary and infectious complications predominating. CONCLUSIONS The present study confirms that free flaps are extremely reliable in achieving successful reconstruction of the head and neck. The incidence of postoperative complications is related to the preoperative comorbidity.