A representative systematic selection of 30% of all 70-year-olds in Gothenburg were invited to a population study. Forty percent of the sample (384 persons) were subjected to a comprehensive dental examination. The participation rate was 84%. The aim of the present study was to describe the function and dysfunction of the masticatory system of the 70-year-olds. 41% reported no symptoms of dysfunction while 46% had severe dysfunction according to HELKIMO'S Anamnestic Dysfunction Index. The clinical examination revealed that only 14% had no signs of dysfunction. 32% had moderate or severe dysfunction according to Helkimo's Index. In more than half of the subjects the masticatory muscles were tender to palpation and in 37% TMJ sounds were diagnosed. Several of the clinical findings were more common in the women than in the men but only concerning tenderness of the TMJ and the masseter muscle were the differences significant. The degree of dental invalidity was measured by Eichner's Index. The Index showed no or only weak relation to the Anamnestic and Clinical Dysfunction Indices. Neither did the degree of dysfunction in complete denture wearers vary with the condition of their prostheses.