INTRODUCTION: Dental caries is most commonly found in school going children due to several reasons, which includes excessive sugar in diet, inappropriate oral hygiene, transition in their dentition & all the permanent teeth except for the third molars will erupt. For these factors, 12-year has been set as the global monitoring age for dental caries. However, because of their recessed gingival condition, older adults have a higher risk of developing root caries. Due to periodontal and dental issues, caries is most severe in the 65–74 age range. AIM: To assess the prevalence of dental caries in 12-years and 65-74-years-old WHO index age groups. METHODOLOGY: Total 400 subjects participated in the survey. 50% of the population consisted of students in Sisarma Senior Secondary School, Udaipur, Rajasthan, and the rest 50% consisted of the patients coming to the Department of Public Health Dentistry, Darshan Dental College and Hospital, Loyara, Udaipur, Rajasthan. The WHO Oral Health Assessment Proforma was used to record the patients’ oral mucosal problems, dentition status, and treatment requirements. Version 26 of SPSS was employed for the statistical analysis. The significance level was set at 0.05 and appropriate tests were employed. RESULTS: Study showed as the age increased the prevalence of dental caries increased with a significance level of 0.00. CONCLUSION: The prevalence of dental caries was found in both the age groups, but it was comparatively higher in age group of 65-74-years and is correlated with the various factors which are included in the study.