Dental caries is a breakdown of teeth due to acids made by bacteria. Dental caries is caused by the action of acids on the enamel surface. The acid is produced when sugars (mainly sucrose) in foods or drinks reacts with the bacteria present in dental bio film on the tooth surface. Dental caries is a major oral health problem in most industrialized countries affecting 60 -90% school children and the vast majority of adults. Dental caries is a preventable public health problem. In the present study, association between good oral hygiene and prevalence of dental caries has been evaluated in a General health check-up camp at Ideal High School, Powai Mumbai -400076.Data was obtained through screening and questionnaire. The data collected was presented in tabular form and statistical evaluation was done. In the present study, strong association between dental caries and bad oral hygiene has been noticed. Observation: In present study total 232 primary school pupils were screened for dental caries, out of which 56 students were found to be affected by dental carries. It shows that 24% of prevalence of dental caries in a students with bad oral hygiene and malnutrition. Conclusion:Children with bad personal hygiene and bad dietary habits were affected more by dental caries. Good oral hygiene and dietary habits were advocated. They were asked to consult dentist for further management.