Aim: This study aims to evaluate the prevalence of three-rooted permanent mandibular first molars in an Indian population. Materials and methods: The intraoral periapical radiographs of 616 patients of Indian ethnicity possessing bilateral mandibular first molars were screened under optimal conditions. A total of 1232 mandibular first molars were evaluated, and the prevalence of three-rooted mandibular first molars and the correlation between left and right side occurrence and between either gender was recorded. Results: The prevalence of three-rooted mandibular first molar was 16.07% of the patient's examined and 11.52% of the teeth examined. There was neither a statistically significant difference amongst the gender nor on the side of occurrence (P > 0.05). The bilateral incidence of a symmetrical distribution was 43.43%. Conclusion: Based on the results of the study, the prevalence of this anatomic macrostructure in an Indian population was 11.52%. Parole chiave: dental anomalies, mandibular molars, radix entomolaris