Background: The outcome of endodontic therapy is associated with eradication of micro-organisms from the root canal system and avoidance of re-infection. Optical magnifications have extended the horizons of dental treatment. Recently, illumination and magnification have established to help provide precise anatomic details. The canal orifices can effortlessly be identified under a microscope than with surgical loupes or the naked eye. Objective: The comparison of the conservation of tooth structure during access cavity preparation under the microscope with the conventional method. Methods: Thirty patients were selected for whom root canal treatment where indicated. The patients were divided into two groups Group 1 __ampersandsignndash; Access cavity prepared conventionally and Group 2 __ampersandsignndash; Access cavity preparation under the microscope. The measurement between intercanal orifice was done using Vernier callipers. Results: In the present study, there was a reduction in measurement between mesiobuccal to the distal orifice and mesiobuccal to mesiolingual orifice but it was not statistically significant. There was a reduction in measurement from mesiolingual to distal orifice. The reduction was statistically significant (p=0.018) Less amount of tooth structure is removed therefore allowing for conservation of tooth structure resulting in improved strength tooth strength, which is clinically important. Conclusion: The conservative endodontic cavity (CEC) preparation to reduce the loss of tooth and preservation some of the roofs of the pulp chamber and peri-cervical dentin was reported in the literature.