In the context of a multidisciplinary study program whose purpose is to investigate the genetic aspects of Huntington's Chorea (HC), the authors conducted an epidemiological descriptive research extended to the population residing in the province of Ferrara in a time period including the years from 1971 to 1987. On December 31st, 1987 we estimated a prevalence rate of 1.89 cases of HC per 100,000 inhabitants; in the years 1971-1987 the incidence rate was of 0.11 per 100,000/year and the mortality rate of 0.06 per 100,000/year. In the last years considered for the study, the incidence and the prevalence showed a relative increase indicating that HC still exists in the ferrarese population, despite a greater public awareness. With the aim to organize preventive actions and to reach the preclinical diagnosis of the disease we singled out 83 subjects at risk the study area.