To investigate the chewing patterns of patients with TMJ disorders, analysis of mandibular movement was performed in 25 normal subjects and 150 patients with stomatognathic dysfunction using the Sirognathograph analyzing system. Patients with TMJ disorders demonstrated different chewing patterns than those of normal subjects. Chewing patterns in the frontal, horizontal, and sagittal projections were classified into four, two, and two different patterns, respectively, and each distinct chewing pattern appeared to be associated with a specific TMJ disorder.