The present study is planned to analyze radiographically examined success and failure of endodontically treated teeth among the patients who came at Taibah dental clinics, Saudi Arabia. One hundred (N=100) endodontically treated teeth were clinically examined by using dental mirror, dental explorer and periodontal probe. The periapical radiographs of these teeth were radiographically examined. Several reasons including defective restoration, periodontal disease, recurrent caries, under filling, poor density obturation, over filling and many others of each root filled canal were recorded in the patient data sheets. Chi square test was applied to determine statistical significance if any. Our study demonstrates 20% success rate of endodontic treatment while failure was recorded in 65% and potential failure in 15% of cases. Clinical data revealed defective restoration in 84% followed by periodontal disease (62%), recurrent caries (52%). When endodontic treatment was radiographically evaluated, periodontal lesion was observed in 74% followed by recurrent caries (73%), under obturation (50%), poor density obturation in (48%) of the cases. Defective restoration, poor density obturation, under obturation and periodontal diseases were significantly (p=0.001) associated with endodontic failure while periodontal disease is posing significantly higher risk of potential failure in this study. The success rate of endodontic treatment was found only in 20% and the most common cause of its failure was defective restoration followed by periodontal lesion, recurrent caries, under filling, poor density obturation etc.