Background: Parents are the first environment for children and parental knowledge is the basis for forming children's positive behavior to maintain oral health with good and correct care. Knowledge of caries is everything that a person knows about dental caries. Parents often consider permanent first molars to be milk teeth that will have replacement teeth when they are extracted so that when these teeth are exposed to caries, the teeth will be left or extracted (Susi, et.al., 2012). Dental caries is a dental and oral disease that mostly affects school-age children, especially in the permanent first molars which only erupt once. Research purposes: This study aims to determine the relationship between parental knowledge about how to brush teeth with caries in the first molar at the Dental BP Gigi UPTD Puskesmas Watubelah Kabupaten Cirebon. Type of Research: using non-experimental methods with cross sectional design, which is to connect research subjects including independent variables and dependent variables, only observing a number of subject characteristics according to the actual situation, without any manipulation from the researcher. The research sample is parents using purposive sampling technique. Data analysis using Spearman 's Rank. Research Results: The level of knowledge of parents about dental caries in good category 8 (40%) respondents, less category 12 (60%) respondents. The caries category of permanent first molars with caries reached enamel 4 (20%) respondents, caries reached dentin 8 (40%) respondents, caries reached pulp 5 (25%) respondents, caries reached root 3 (15%) respondents. Conclusion: There is no relationship (H0 is accepted) between parents' knowledge about how to brush their teeth with caries in the first molar at the BP Gigi UPTD Puskesmas Watubelah Kabupaten Cirebon where the p value is 0.641 (> 0.05) which means it is greater than = 0, 05.