Epidemiology of child and adolescent mental health is a relatively new discipline, particularly in the province of Quebec. Some work has however estimated the prevalence of the most common mental disorders among young people, such as anxiety and depression, as well as identified associated individual, family and socio-economic variables. This article has two objectives: to present a review of major epidemiological research findings in child psychiatry conducted in the province of Quebec and highlight the contribution of these findings for public health. To achieve these objectives, this article presents the results of research related to three themes: 1) measurement and identification of anxiety and depressive disorders in children and adolescents, 2) the prevalence of these disorders and comorbidity, 3) the correlates of anxiety and depressive disorders identified in epidemiological studies. The authors will then highlight future implications of these results across Québec policies in the field of public health.