Guided tissue regeneration is a technique for directing cell growth towards specific areas of the periodontium damaged by periodontal disease, endodontic pathology or trauma. Periapical tissue regeneration will occur predictably after endodontic surgery if intra- and extra-radicular infections are controlled by adequate root-end resection and complete retrograde seal of the root canal. Indications for GTR technique in endodontic surgery are limited they include: combined endodontic-periodontic lesions, through-and-through bone lesions, and large periapical lesions almost involving the alveolar crest bone. The materials, such as barrier membranes and bone grafts used in GTR technique should be biocompatible .GTR technique in endodontic surgery could improve periapical wound healing in through-and through bone lesions and possibly in cases with large periapical lesions. This dissertation will explain about guided tissue regeneration techniques in endodontics, its principles, and materials used, healing after GTR, complications of GTR and their prevention.