PURPOSE: Major chest wall reconstruction following radical excision of advanced breast cancer is remained a challenging treatment of oncoplastic surgeons. The aims of this study are to introduce a method of external oblique myocutaneous flap (EOMCF) and evaluate the effect of large chest wall reconstruction using external oblique myocutaneous flap. METHODS: A retrospective review of 17 patients who underwent chest wall reconstruction with external oblique myocutaneous flap from January of 2007 through May of 2008 was performed. The upper edge of external oblique myocutaneous flap was lower margin of defect. The medial edge was mid-line of abdomen by umbilicus, vertically along the linea alba. The lower edge was a lateral transverse line at the level of umbilicus. The flap was rotated clockwise in the left side chest wall defects and counterclockwise in the right. RESULTS: The mean chest wall defect was 360.8+/-137.8 cm2 and the mean flap size was 591.1+/-136.2 cm2. The mean reconstruction time was 41.5+/-7.9 min and patients were discharged on 8.8+/-1.2 postoperative day (mean). Three patients had superficial skin loss (<5%) and this lesions are healed with conservative therapy. CONCLUSION: We propose that the external oblique myocutaneous flap may be a safe and feasible method for reconstruction of large chest wall defects after radical mastectomy including all breast skin.