Orthodontic treatment for adults can be difficult because they often have several problems, including some associated with aging. This article reports the successful use of miniscrews to treat a 51-year-old woman with Class III malocclusion, unstable occlusion, periodontal disease, and temporomandibular disorder. The patient had a skeletal Class III jaw-base relationship, anterior and unilateral posterior crossbites, and a deviated midline. It was therefore necessary to confirm her mandibular position with a stabilization splint. Miniscrews were implanted in the retromolar area and used to move the mandibular teeth en masse distally. After orthodontic treatment, the mandibular molars and anterior teeth were moved distally, and the patient had a stable occlusion. Acceptable occlusion and periodontal health were maintained after 1 year of retention. Our results suggest that miniscrews are useful for en-masse distal movement of mandibular teeth in aging patients.