Caries and gingivitis are the most prevalent diseases in Chile. The aim of this study is to determine the damage of oral health in children ages 4 and 5 years, in Peralillo, Chile, prior to the start of oral health program promoted by JUNAEB (Junta Nacional de Auxilio Escolar y Becas) in the commune. The sample consisted of 130 children, admitted to the student dental clinic between November 2010 and February 2011. Oral exam seeks to know presence of dental caries and number of teeth affected, using dmft index (decayed, missing and filled primary teeth), simplified oral hygiene index (OHI-S) and presence or absence of gingivitis. 49.2% of children had caries, with an dmft index 2.4 (S.D. ± 3.5). The OHI-S of the entire sample was 1.4 (S.D. ± 0.4). Gingivitis was reported in 9.2% of cases. The results of this investigation shows that following dental intervention, the goals set by FDI (FDI World Dental Federation) and WHO (World Health Organization) were obtained. Efforts are required in promotion and education in oral health, as well an increase in resources to attend these patients to decrease impact of oral diseases in the future.