The aim of this study is to introduce the endoscopic subcutaneous mastectomy without skin excision as the standard surgical technique for grade IIB and III gynecomastia. Endoscopic subcutaneous mastectomy was performed successfully in 125 breasts of 65 patients with Simon's grade IIB and III gynecomastia. The volume of gland resected in the 125 breasts was 80 to 300 mL, with the mean of 146 mL. The operation time was 65 to 155 minutes, with the mean of 82 minutes. There were a few operative complications, including partial nipple necrosis in 2 cases and subcutaneous hydrops in 1 case; but no complete nipple necrosis, subcutaneous emphysema, postoperative active bleeding, local skin necrosis, or operation-side infection occurred. Satisfactory chest contour was gained in all cases without any abnormity, skin redundancy, or recurrence during the follow-up of 3 to 36 months. Endoscopic subcutaneous mastectomy is distinctive and practicable in manipulation as well as safe and can get esthetic effect. It is a new choice for the treatment of gynecomastia.