['To determine whether mouth breathing children present the same cephalometric patterns as patients with obstructive sleep apnea syndrome (OSAS).', 'Cephalometric variables were traced and measured on vertical lateral cephalometric radiographs. The cephalometric measurements of 52 mouth and 90 nose breathing children were compared with apneic patients. The children had not undergone adenoidectomy or tonsillectomy and had not had or were not receiving orthodontic or orthopedic treatment.', 'Mouth breathing children showed same cephalometric pattern observed in patients with OSAS: a tendency to have a retruded mandible (p=0.05), along with greater inclination of the mandibular and occlusal planes (p<0.01) and a tendency to have greater inclination of the upper incisors (p=0.08). The nasopharyngeal and posterior airway spaces were greatly reduced in mouth breathing children, as observed in patients with apnea (p<0.01).'] Do mouth breathing children have cephalometric patterns similar to those of adult patients with obstructive sleep apnea syndrome?