The authors have performed a clinical and epidemiological study on 162 immunocompetent children with herpetic gingivostomatitis, during 1982-1991. They have observed a peak age of incidence between 9 and 28 months, absence of sex differences and seasonal variations, and a prevalence of patients of lower social status. HSV I was the most frequent aetiological agent and it was not always possible to recognize the source of contagion. The patients have been graded in three classes (severe, moderate and mild disease), according to clinical manifestations of gingivostomatitis, and the severe form was the most frequent with a prevalent orolabial involvement. The prognosis of the disease was satisfactory in all patients, even if more favourable in acyclovir treated children because of fast regression of the symptoms.