The present radiographic and clinical survey was performed to study the prevalence of "incipient juvenile periodontitis" in a population of 16-year old adolescents in Switzerland. The subjects to be screened were selected on the basis of the population distribution in the year 1980 in the territory of Switzerland. 7% of all 16-year old adolescents proportionally distributed into the different ethnic groups of Switzerland were incorporated in the study. From the school dental systems, a total of 7604 pairs of bite-wing radiographs were obtained and evaluated for fillings and iatrogenic factors, gross amounts of calculus, resorption of alveolar bone. A diagnosis of "incipient juveline periodontitis" was given if the clinical criteria of this disorder proposed by Baer were met. In 7142 pairs of bite-wing radiographs, such a diagnosis was attributed to 7 female and 12 male patients. Subsequently, they were asked if they would be examined at the University of Berne School of Dental Medicine. On the basis of history, a complete periodontal chart and full mouth radiographs, the diagnosis was confirmed or refuted. 8 patients (4 female and 4 male) were definitely diagnosed as "incipient juvenile periodontitis". This resulted in a prevalence of 0.1% with a ratio of female to male of 1:1 in the country of Switzerland at age 16. As in other industrialized countries, this prevalence seems not to be a major public health problem.