Total lower lip reconstruction was accomplished by combining a radial forearm free flap with a masseter muscle transfer. The patient, who had T4 carcinoma, had the entire lower lip resected including the depressor anguli oris muscle. A radial forearm flap was used to reconstruct the lower lip lining and the floor of the oral cavity. The right and left masseter musculofascial flaps were elevated and transferred in the medial-superior direction, and the peripheral margins of the flaps were sutured together. The lateral margins of the flaps were then sutured to the orbicularis oris muscle of the upper lip. Good sphincter function was obtained more than 1 year after the operation, electromyography revealed almost normal mobility of the transferred masseter muscles, and no sagging of the masseter muscle sling was observed. This procedure appears to be effective for the reconstruction of sphincter function of the lower lip after wide excision of the entire chin.