Periodontal disease is one of the well-documented complications of diabetes mellitus in adulthood. The effects of diabetes mellitus on periodontal tissues in children and teenagers have been studied only in more recent years. Although clinical studies have demonstrated a few cases of severe periodontal disease in patients with "historical" diabetes mellitus, in the overwhelming majority of cases periodontal lesions seem comparable in young subjects with and without diabetes mellitus. However, reports on this topic published both in France and in the United States fail to give a clear picture of the existence, prevalence and severity of peridontal disease in youngsters with diabetes mellitus. Consequently, an epidemiologic study was undertaken at the Herold Hospital (Paris) and at the Association of Young Diabetics. Eighty-five young patients with diabetes mellitus and 38 controls were included. The purpose of the study was to determine whether periodontal disease is only a former or still a current complication of diabetes mellitus.