A large full-thickness defect of the lower lip is difficult to reconstruct. Preservation of eating and speaking functions based on maintenance of oral sphincter and muscle function, sensation, and the oral aperture are the basic aims. It is also important to achieve a good aesthetic appearance. Here, we describe a new procedure using combined bilateral hatchet and nasolabial advancement flaps for a large full-thickness defect of the lower lip. The aim of use of the hatchet flap is to make a natural curve from the mentolabial fold to the mental protuberance using the "dog ear" resulting from suturing medially advanced bilateral hatchet flaps and to preserve a more certain blood supply to the medial edge of the flap. Our results indicate that the procedure using combined bilateral hatchet flaps and nasolabial flaps is useful for a U-shaped large full-thickness defect, with good functional and aesthetic outcomes.