Although new treatment modalities like free flap management techniques have been widely performed, the sternocleidomastoid (SCM) flap still offers one of the best choices in repair of defects in the head and neck region. In this case, there was full-thickness soft tissue defect in the floor of a twenty year-old man's mouth due to a high velocity missile injury. It was reconstructed by using bilateral SCM flaps successfully because it was the most reliable and versatile technique and neglected more complicated procedures.