Aims: To determine the efficacy of amitriptyline and the optimal dosage for treating a somatoform pain disorder in the orofacial region. Methods: Thirty outpatients with orofacial pain who fulfilled the criteria of pain disorder were recruited for the study. Twenty-three patients had specific precipitating events in their past history, which they considered to be the origin of the pain. Amitriptyline was administered and the dose was gradually increased up to a daily dose of 250 mg. The response to treatment was evaluated using a numeric rating scale and the Clinical Global Impression Scales. Results: Five patients dropped out and 25 patients (83%) completed the trial. Twenty-two patients became pain free or nearly pain free, while 3 patients who also completed the study did not respond at all, even though they took a daily dose of 250 mg amitriptyline. For responders, the mean daily dose of amitriptyline was 77.5 ± 51.5 mg (range, 10 to 200 mg). Four patients (16%) obtained pain relief with a daily dose of less than 50 mg, while 3 patients (12%) needed a daily dose of 150 mg or more for pain relief. Adverse side effects were observed in 19 patients. Conclusion: Amitriptyline was effective in relieving pain associated with a somatoform pain disorder in the orofacial region. The dose of amitriptyline may need to be as high as that used to treat a major depression. Keywords: orofacial pain, pain disorders, amitriptyline, tricyclic antidepressants (TCAs), precipitating event