The aims of the present study were to investigate if there are differences concerning preferred body posture during sleep between 100 patients, 66 women and 34 men, mean age: 49 years (range: 20-85 years) referred to a specialist clinic because of TMD and 100 matched controls from a public dental clinic. The participants were asked to answer a questionnaire with questions about TMD symptoms and neck or shoulder pain. They were also asked about preferred sleeping position as well as about perceived sleep quality. No differences could be found between the two groups in respect of sleeping position. However, significantly more individuals in the TMD group compared to the controls had changed their preferred sleeping position due to their face and/or jaw and/ or neck-shoulder symptoms. Subjects in the TMD group also more frequently stated that they often felt insufficiently rested at awakening and/or felt tired or sleepy in the daytime because of symptoms from face/jaws. A significant number in the control group reported TMD symptoms indicating a latent need for TMD treatment. It is concluded that sleep position seems to have little or no significance for the development or maintenance of TMD symptoms. However, the study indicates that TMD symptoms and associated neck- and shoulder pain affect the quality of sleep.