Introduction: Even when the most stringent endodontic treatment and/or retreatment are followed, apical periodontitis can persist, leading to periodontal ligament (PDL), cementum, alveolar bone and dentine destruction. In these cases, surgical endodontic treatment, if performed using the operating microscope (OM), minimal root resection, ultrasonic root end preparation and biocompatible root end filling materials, can achieve a success rate of more than 90%. Endodontic surgical procedures have been completely transformed by the incorporation of the OM with new resources, such as piezosurgery devices and specific microsurgery ultrasonic tips, flexible micromirrors, microexplorers, mini endodontic curettes, micropluggers and micro suturing instruments. The OM can optimize all the steps of an endodontic microsurgery, including flap preparation, osteotomy, root apices identification, root end resection, inflammatory tissue removal, resected root surface observation, root end preparation, root end filling and suturing. The aim of this article is to present all the steps of modern endodontic microsurgery and to describe the new resources available in the market to improve the success rate of this modality. Conclusion: The use of modern endodontic microsurgery techniques significantly improves the success rates of the therapy when compared with traditional techniques