The wide excision of advanced carcinoma in head and neck area remains surgical defects. The defect of head and neck area has been reconstructed by using skin graft and local, regional, distant, and free flap. The use of myocutaneous flaps, which provide both muscle bulk and skin coverage, represents a significant advancement in reconstructive surgery and most widely used. The pectoralis major myocutaneous flap as noted by Ariyan and Krizek, is used most frequently due to advantages such as improved vascularity, bulk, long arc of rotation and one-stage reconstruction. The authors analyzed the age and sex, primary, disease, viability, size and location of defect, complications of our experiences with 14 cases of pectoralis major myocutaneous flap used in reconstruction of oral cavity and oropharynx recent 5 years. The results were as follows ; 1) 14 cases were reconstructed with pectoralis major myocutaneous flaps and all cases were squamous cell carcinoma. 2) Viability of flap were relatively poor in the reconstruction of floor of mouth, especially anterior floor of mouth. 3) In the viability of flap according to defect size, the smaller defect size, the poorer viability.