Quality of obturation is one of the factors that influences the outcome of endodontic treatment. Thus the present study was conducted with the aim to determine the influence of length and quality of obturation on the failure of endodontic treatment. For the purpose of data collection, the preoperative radiographs of failed endodontic cases reported to the institute between June 2019 and April 2020 were analysed. Data was tabulated in excel sheet as poorly filled canals, obturations short of apex, obturations extending beyond the apex and adequate obturation. Further, the teeth were grouped into six categories as maxillary anterior, premolar and molars and mandibular anterior, premolar and molars. A descriptive statistical analysis and chi square test was performed. The results were represented in the form of tabulation and bar graphs. Of the 225 cases that matched the inclusion criteria, maximum endodontic failures were seen in maxillary anteriors (41.8%) followed by mandibular molars (25.8%) and maxillary molars (13.3%). Of these endodontic failure cases, 144 were due to poor and incomplete obturations (64%) 58 obturations were homogenous but short of the apex (25.8%). Only 15 cases were reported with over obturation (6.7%) and 8 radiographs depicted adequately obturated teeth undergoing endodontic failure (3.6%). Poorly filled canals were the primary reason that contributed to the majority of endodontic failures.