Interviews on the occurrence of Myofascial Pain-Dysfunction (MDP) Syndrome were held with a group consisting of 246 individuals 25 years of age. Every fifth interviewee said she/he had experienced clicking/crepitation from the TMJs. Five percent had felt pain when opening the mouth wide and 3% while chewing, yawning or talking. These frequencies of symptoms were much like those found in a probability sample of the total adult population in Norway and a probability sample of elderly Norwegians. In the present study, 28% said they had some or much headache recently. These symptoms varied with background characteristics, especially with sex. There was also a relationship between headache and MPD-symptoms. By combining the effect of the variables sex and headache upon the frequency of reported clicking/crepitation, it was tripled.