Since the concept of myocutaneous flap reconstruction of the head and neck region was introduced it has opened a new approach to surgical management in this area. This flap not only reduced the number of operations as compared to "staged procedure," but also reduced the costs of medical care. We are, however, experiencing significant failures as the applications of this flap are extended. This paper reviews our experience with myocutaneous flaps in 15 partial and total failures. An evaluation of these failures reveals that most occurred l½ to 3 weeks after reconstruction. The factors predisposing to failure seem related more to technical errors rather than to general factors. Diabetes, peripheral vascular disease, malnutrition and low hemoglobin, and low blood pressure were not major contributors to the failures in our series. Local factors predisposing to failure of myocutaneous flaps can be divided into two large categories — arterial failure and venous failure. In our series of unsuccessful myocutaneous flaps, the major factors appeared to be venous stasis leading to arterial insufficiency. All failures had developed after the initial critical period of flap survival (7-10 days). The following techniques showed an especially high rate of failure: 1. SCM — myocutaneous flap to resurface floor of mouth. 2. Tubed pectoralis myocutaneous flap to reconstruct pharynx and esophagus. 3. Flaps developed with very narrow vascular pedicles. Individual cases representing delayed failure are presented.