Fusion is a rare developmental dental anomaly and its definitive diagnosis is of great importance for successful endodontic treatment.A twenty-five-year old female attended the Endodontic Department with the chief complaint about dysmorphic right front tooth and a history of vague pain since the previous 11 months, which had ceased during last one month. Oral cavity examination was performed, endodontic oriented sensitivity tests including cold, hot, and electric pulp tests were conducted, and periapical radiography was also ordered.Oral cavity examination revealed an enlarged permanent right maxillary incisor with deep caries on the lingual surface. All vitality tests were negative. Examinations were normal except for one missing tooth in the total count in the upper right quadrant. Periapical radiography clarified a fused maxillary central and adjacent lateral incisor with large coronal radiolucency involving the pulp and a periapical radiolucent area suggestive of a chronic apical periodontitis. The final diagnosis was established as fused maxillary incisors with necrosis and chronic apical periodontitis. A conservative non-surgical root canal therapy was planned and careful negotiation and obturation were performed after obtaining the informed consent, followed by the esthetic reconstruction. A six month follow-up revealed that periapical radiolucency had almost disappeared, the teeth were in function, and the patient reported no complaint.