Dental caries is considered as the major health problem among children studying in school in Bangladesh. The aim of the study is to evaluate the pervasiveness of dental care and oral hygiene among school children aged 6 to 12 years old. A cross-sectional descriptive survey was carried out at Department of Dentistry, Bangladesh Shishu Hospital & Institute, Dhaka, Bangladesh from January to June 2023. Total 100 dental caries is considered as the major health problem among children studying in school in Bangladesh. The pervasiveness of dental caries was evaluated with WHO criteria, and to evaluate oral hygiene of school children the questionnaire method was used. All participants were asked 13 questions closed-ended questions. The population studied consisted of 100 school children from the ages of 6 to 12 years in public schools, Dhaka city. There were 46 (46.0%) female and 54 (54.0%) males' students. Table 1 shows the prevalence of dental cavity among the students and the relation between gender and dental cavity. The oral examination of the students found that 63.0% have dental cavity while 37.0% don’t have dental caries. The results also showed that 59.2% of males have dental cavity while 67.4% was for females. P-value was 0.086 which was more than 0.05, that there wasn’t a statistically significant difference between gender and dental cavity. The results of this study revealed that the dental caries was a bit high among the participants and welfare oral hygiene among the target children. For recommendation we advise to take care of oral hygiene in regard with cleaning the mouth and regular visiting the dentist. Therefore, this study could benefit all the students and can provide at least a authority for the development of school oral health program to encourage students for oral hygiene practicing that help to decrease the level of dental caries.