Dental crowding is frequently associated with transverse jaw discrepancies, resulting in a less-than-ideal position of the teeth in the basal bone. The classic aproach for correcting bimaxillary crowding are extractions or arch expansion. Rapid maxilla-mandibular expansion was used to treat transverse discrepancies in growing patients, but with aging, the upper and lower jaw bones become increasingly resistant to expansion. The surgically assisted rapid maxillary expansion (SARME) and the mandibular midsymphyseal distraction osteogenesis procedure overcome this age limitation and are of great importance for the treatment of transverse discrepancies in adults. The aim of this paper is to report a case with a severe transverse deficiency treated with SARME, mandibular midsymphyseal distraction together with orthodontic treatment in an adult patient. The case highlights the esthetic advantages of increasing the transversal dimension of both jaws in patients with severe crowding associated with constricted dental arches and recommends the maxillo-mandibular transverse distraction osteogenesis as an and effective form of surgical treatment for patients with malocclusions or dentofacial deformities featuring severe transverse discrepancies, combined with a carefully monitored orthodontic treatment.