A randomized empirical study investigated whether hypnosis audio CDs were a suitable and effective treatment for patients with craniomandibular dysfunction (CMD). The purpose of the study was to determine whether selfhypnosis at home using a CD with relaxation suggestions would relieve pain and improve the mobility of the mandible. Investigations were carried out over a four-week period. In addition, we investigated if any gender-related differences could be found. Patients and methods: After a clinical functional analysis according to Ahlers/Jakstat, 20 patients were randomly assigned to each of three study groups. The splint group was treated with an occlusal splint in the maxilla (Michigan Splint according to Ramfjord). It was compared with a CD group, in which the patients had listened to a relaxation CD (according to Schmierer). In the control group, patients were only informed about the causes for their disease and the treatment options for CMD, but received no further treatment. The change of the distance between the incisal edges when the patient opened his or her mouth actively to the maximum (active IED, as measured with the CMDmeter) was used as the criterion to assess functional impairment. The subjective perception of pain was assessed using a numeric analog scale (NAS score). The observation period was four weeks. Wilcoxon's and McNemar's test were used for statistical analysis, as were non-parametric (Mann-Whitney U and H test) and parametric methods (t-test, analysis of variance). Results: A comparison between the baseline examination and the last follow-up examination after four weeks showed a significant reduction of pain intensity and impairment by pain both in the splint group and in the CD group. No age- or gender-related differences could be found for the different parameters. In addition, a correlation analysis was used to determine whether the individual stress levels had an influence on the development of the variables pain, impairment by pain and active IED. Those patients with high scores on the stress indexes at baseline achieved more positive treatment results than patients with lower scores. Conclusion: The study results show that self-hypnosis using audio recordings is a positive enhancement to the initial treatment of CMD patients. Pain reduction seems to be independent of age or sex but dependent on the previously experienced stress levels. Keywords: CMD, distance between incisal edges, hypnosis, pain intensity, splint therapy