This paper gives the age- and sex distribution of symptoms of dysfunction of the masticatory system in 321 Lapps in Northern Finland. According to both an anamnestic and a clinical dysfunction index roughly the same prevalence of dysfunction was found among men as among women. The few sex differences which were found were small. Women had a significantly higher frequency of headache, pain in the neck and shoulders and fatigue of the jaws. On the average women had a worse dental state than men, who on the other hand reported luxations of the TMJ and some biting para-functions more frequently than women. The age distribution was remarkably even for most of the recorded symptoms. General symptoms as headache, general joint and muscle symptoms, however, increased in frequency with age. For some of the anamnestic variables (oral parafunctions, feeling of fatigue of the jaws and facial pain) the age group 35-44 years showed the highest frequencies. The lowest frequencies of both anamnestic and clinical symptoms were found in the youngest age group (15-24 years). The findings in this study differ markedly from earlier studies on clinical materials reporting a skewed sex- and age distribution. The conclusion is that results from studies concerning age- and sex distribution of patients with functional disorders of the masticatory system, are not representative for the distribution of such symptoms in the general population.