In a study The Special Region of Yogyakarta (DIY) has a prevalence of tooth and mouth problems of 32.1%. Dental and oral health problems are influenced by people's knowledge about the importance of maintaining dental and oral health. One of the ways that able to help in understanding and controlling dental and oral health is the level of knowledge of each individual, thus can increase awareness about oral and dental hygiene. Elementary school children (SD) generally do not know and have not been able to maintain the health of the oral cavity, parents are the one who must be responsible and concern about it. Objective: To determine the relationship between parent’s knowledge about dental and oral hygiene status of children aged 9-10 years at Ngebel Gede 1 Public Elementary School, Sleman Yogyakarta. Research methods: The design of this study was observational analytic with a cross sectional approach. The sample was determined by purposive sampling as many as 37 students from the Ngebel Gede I Elementary School Sleman Yogyakarta. The data analysis used spearman test. Research results: Show that the value of p 0,000 with a correlation coefficient (r = -0,993) which means that there is a strong relationship between the level of knowledge of dental and oral health and the dental and oral hygiene status of children. Conclusion: There is a relationship between the parent’s level of knowledge about dental and oral health with dental and oral hygiene status of children aged 9-10 years at Ngebel Gede 1 Public Elementary School, Sleman, Yogyakarta The better the parent’s level of knowledge about dental and oral health, the better child’s dental and oral hygiene.