The present study was based on the finding of a case of prepubertal periodontitis, a low prevalence pathology. One hundred and fifty-two infant patients attending the Department of Odontopediatrics of the Faculty of Dentistry of the National University of Rosario over the period April 1995-September 1996 were included in the present study. The reason for consultation was dental caries. However, the high general prevalence of gingivitis (50%) was remarkable. This may be due to deficient oral health care awareness at home and at school. The prevalence of prepubertal periodontitis (PPP) in the population under study (one case of localized PPP) was 0.66%. These data are in agreement with international reports that account for a prevalence value of less than 1%. A relevant difference with other reported cases could be that this patient complained of upper respiratory tract disorders and, occasionally, ear infections. These symptoms appear in the generalized but not the localized forms of the disease.