Background: Dental and oral disease is ranked tenth of disease in Indonesia, 28,9% problems occur in children. Lack of children’s oral hygiene is one of the factor. Parents role and oral health knowledge is important to maintain their children’s oral hygiene. Lack of parent’s knowledge may have related with children that ignore oral hygiene. Purpose: The aim of this study is to find out the relation between parent’s knowledge level of dental and oral health and oral hygiene status of their children aged 6-12 years at RSGM UMY. Method: This is an analitic observational with cross sectional design. The sample was taken with accidental sampling method and is found sampling were 69 parent’s that took their children to RSGM UMY to got treatment. The instrument used were questionnaires for parent’s knowledge and PHP-M oral hygiene forms for children. Result: The spearman analysis result showed that P is 0,000 and correlation coefficient is 0,607 which means there are relation between parent’s level of oral health knowledge and children’s oral hygiene status. Conclusion: There are moderate relationship between parent’s dental and oral health knowledge level on 6-12 years old children’s oral hygiene status. Parents with high level of dental and oral health knowledge have children with high oral hygiene status.