The purpose of this study was to evaluate the effect of occlusal treatment on the symptoms of temporomandibular disorders (TMD) by questionnaire. Three hundred sixty-nine consecutive TMD patients who had finished treatment in our TMD clinic from April 1985 to March 1995 were included in this study. Questionnaires were sent to the patients, and 260 (80.5%) patients returned them. These patients were divided into two groups. One was the occlusal treatment (OT) group (mean age: 49.3±16.3, male/female=20/114) who received occlusal treatment. The other was a non-occlusal treatment (n-OT) group (mean age: 36.3±16.1, male/female=34/92) who did not receive occlusal treatment. The prevalence of pain in theorofacial region at the first visit was 66.9% in the OT group, and 73.3% in the n-OT group. The questionnaire included a visual analogue scale of pain (VAS), maximum range of opening (MRO), patient's estimation of treatment outcome (TO score), and daily activity limitation attributable to TMD symptoms (DAL score). As a result, no statistically significant difference could be found between the two groups for the three variables (Mann-Whiteney U-test). However, the TO score showed statistically significant difference for the three variables (Mann-Whiteney U-test).