Purpose: This quasi-experimental study was conducted to identify the effects of dental health education on dental health knowledge and dental hygiene status in preschoolers. Methods: Forty-one children were recruited from two daycare centers, one of which served as the experimental group and the other as the comparative group without dental health education. Dental health education consisted of knowledge-oriented lecture and individual practice with a tooth simulator. The dental health knowledge was measured using a self-report questionnaire and dental hygiene using a dental plague index. The measurements were taken before and after the education program in the experimental group while only before the education program in comparative group. Results: Increases in dental health know ledge and decreases in dental plague index were observed 4 days after the education and lasted at least 8 days after the education, Conclusion: The findings of this study indicate that dental health care education consisting of a lecture with simulation practice can be effective in improving dental health care in preschoolers at day care center.