Introduction Tooth loss is a health disorder of the elderly population that may lead to masticatory deficiency and nutritional risks, inducing the biochemical changes of metabolic syndrome (MS). Objective To verify the relationship among number of teeth, anthropometric measurements, and MS in a group of elderly people. Material and method The study was developed in Porto Alegre, RS, Brazil, and it was divided into three phases. The first phase collected information from the database of all project participants and the second one collected sociodemographic, anthropometric, and biochemical data. The third phase was divided into two other phases: first, oral health interviews were applied to the elderly (281 patients evaluated by telephone and 23 visited at home) and second, 45 patients were randomly selected and invited to validate the data obtained by telephone with oral clinical examinations performed by a trained dental surgeon. The sample consisted of 304 individuals. The data collected were tabulated and analyzed using statistical tests. Result Elderly women with severe tooth loss present a significantly higher risk of developing MS. Thus, the maintenance of natural teeth in the elderly is a protective factor for the syndrome. Conclusion The findings support the hypothesis that the oral health of individuals, expressed by the number of teeth, may compromise and increase the risk of MS in the elderly.