Purpose: To describe dental caries experience by age and gender among preschool children in a health district in northeast Italy and to plot a trend of primary-dentition dental caries prevalence and severity over a 27-year time span (1984-2011). Materials and Methods: In a cross-sectional survey, 27 out of 88 kindergartens were randomly selected with a sample of 2603 preschoolers drawn from a population of 8328 3-, 4- and 5-year-old children. Dental caries (d3 t) experience according to the criteria of the British Association for the Study of Community Dentistry was evaluated by two calibrated examiners at schools in 1960 (75.3%) 3- to 5-year-old children from October 2010 to May 2011. Three previous surveys performed in the same area, applying the criteria of the World Health Organization, were used to plot a trend over a 27-year period. Comparisons between groups were made using Pearson's chi-squared test, and caries occurrence was established by logistic regression analysis to assess the influence of sex and age (independent variables) on caries experience (dependent variable). Results: Prevalence (%) and severity (mean dmft ± SD) increased with age (17% and 0.5 ± 1.7 at age 3; 24% and 0.8 ± 2.2 at age 4; 35% and 1.3 ± 2.6 at age 5). The level of untreated caries was 85.8%. No statistically significant difference was found for gender. From 1984 to 2004, the prevalence and severity of caries declined at all examined ages, but were unchanged from 2004 to 2011. Conclusion: The current caries scores in preschoolers are low and similar to those reported in other western European countries. Nevertheless, as very early childhood is a key opportunity to intervene, an effort must be made to provide clear oral health guidance and increase the cooperation among all health professionals. Keywords: caries, epidemiology, preschoolers, trend of caries experience