Aim: Successful root canal therapy requires an in depth knowledge of root anatomy and canal morphology. Generally the maxillary first molars have three roots and four canals. Unidentified second mesiobuccal canal may result in failure of the root canal treatment in maxillary first molar. The aim of the study was to compare the efficiency of dentist with unaided eye(UAE), assisted with surgical loupes (SL) or Dental Operating Microscope (DOM) in locating second canal in the mesio buccal root of the maxillary first molar in patients undergoing root canal treatment. Materials & Method : Access cavity preparation was done for maxillary first molars in 50 patients. A thorough visual examination to locate the second mesio buccal canal was carried out. If canal was not identified, further evaluation was done with SL. If canal was not found under SL, then DOM was used. In each method appropriate irrigation, lubrication, exploration and negotiation of the canal was performed with required armamentarium. Photographic documentation and multiple angled radiographs were taken. Results: Out of 50 patients, second mesiobuccal canal was located in 11 patients with UAE, 20 with surgical loupes, 37 under Dental Operating Microscope. DOM showed statistically significant difference in comparison with SL and UAE. SL showed no statistically difference in comparison with UAE. Conclusion : The use of DOM proved to be a better aid in location of the second mesio buccal canal than SL and UAE.