Aim The purpose of the present research was to assess the efficacy of endodontic re-treatment of root canal filing and associated periapical changes based on radiographic interpretation. Methodology In our study around two hundred radiographs of endodontic treatment which has failed, were evaluated. In these cases, the periapical status was assessed with the help of scoring system known as periapical index (PAI). More than 3 PAI reveals presence of periapical lesion.