Background: The association between certain systemic diseases like diabetes, cardiac disorders and ABO blood group is a well-documented fact. The studies conducted on the association between dental caries and ABO blood group till date is limited. This study was conducted to find out whether ABO blood group affects the prevalence of dental caries. Methods: Based on a pilot study, sample size calculation was performed. A total of 198 patients of 19-59 years age group attending the outpatient department of Conservative Dentistry & Endodontics were randomly selected for the study. Patients free from any systemic diseases and holding a valid certified copy indicating ABO blood group, obtained from a registered pathological laboratory or government institute were selected for the study. Dental caries was scored using DMFT index. Results: Blood group O was found to be more prevalent among the subjects and had the highest mean DMFT score and blood group AB the lowest among all groups. The results were statistically significant. Conclusion: Based on the results of this study, an association between blood group and dental caries prevalence was found. For more conclusive results to be extrapolated to a larger population, further studies need to be conducted on a on a higher sample size.