Introduction- The endodontic therapy is mainly done to prevent or heal apical periodontitis. Due to highly variable root canal anatomy, cleaning and shaping procedures are highly affected. Methodology- The main purpose of this study was to assess the prevalence of middle mesial canal in mandibular first molars using three -dimensional imaging in the population of North India using spiral CT. Results- Three hundred mandibular first molars were examined for the present research. 36 (16.4%) of the 300 teeth have MM canals. The remaining 15 (41.6%) MM canals have been branching off from either the middle or apical third of the MB or ML canals. Of the 36 MM canals identified, 5 (13.88%) had a completely saperate orifice from the MB and ML canals, 18 (50%) shared the same orifice with either the MB or ML canal, and the remaining MM canals were 15 (41.6%). Of the 36 MM canals, only 4 (11.11%) possessed a distinct apical foramen. Conclusion- The MM canal originates as a separate orifice but apically joins the MB or ML canal, and independent: The MM canal originates as a separate orifice and terminates as a separate apical foramen.