Peripheral branches of the facial nerve, the marginal mandibularis in particular, are vulnerable to injury during facial surgery, i.e., submandibular gland surgery, flap development in radical neck dissection, liposuction of the jowl area, percutaneous insertion of a screw for mandibular plating, especially at the angle of the mandible, and elevation of the superficial musculoaponeurotic system (SMAS) in rhytidectomy. There is no technique available to locate the peripheral branch of the facial nerve preoperatively so that the area containing the nerve branch can be avoided in making an incision or in developing a tissue plane. Unlike the otoneurological or neurosurgical procedures, the facial nerve branches are not actively explored in facial plastic surgery. Instead, the purpose of many techniques developed in the past is to avoid dissecting an area where the nerve might be located. The author developed a new method that can preoperatively and percutaneously identify and map the course of the peripheral branch of the facial nerve. Percutaneous facial nerve mapping (PFNM) allows a surgeon to make his or her incision in a more favorable location, as the exact course of the facial nerve is already visualized by the mapping technique. A tissue plane adjacent to a facial nerve can be dissected more safely and aggressively, where and whenever necessary. Of 57 cases studied since August of 1994, the mapping was possible in most patients, except for earlier cases in a developmental stage.