Background: Knowledge of children's dental health is essential for parents, particularly mothers, because it can affect the development and growth of children's teeth. Dental caries is the most serious issue in children's dental and oral health. Based on a direct approach to ten mothers, 7 children under the age of five had dental caries, and 3 children under the age of five did not have dental caries. Therefore, children under the age of five require special attention because they are more vulnerable to dental and oral health issues. The aims of study: Knowing the description of education and working on mother's knowledge in preventing dental caries for children under the age of five at Jalak Posyandu in Kradenan, Girirejo, Imogiri, Bantul, Yogyakarta. Research methods: This is a descriptive study using a cross-sectional survey design. The sampling method used the total sampling technique with a sample of 50 respondents. The findings of study: The findings revealed that the level of knowledge about brushing teeth and the amount of caries in mothers who had toddlers, the majority of respondents were highly educated and worked in the category of knowledge on preventing dental caries, which were 18 respondents (36%). Conclusion : Respondents' education, occupation, and level of knowledge are classified as high education, work, and knowledge. Keywords: Education, Work, Knowledge, Dental Caries, Toddler.