Dens invaginatus is a developmental malformation of teeth that most commonly affects permanent maxillary lateral incisor. The clinical importance of dens invaginatus results from the risk of pulpal disease. The presence of dens invaginatus with internal resorption is extremely rare. Hence, all clinicians should be aware of this anomally. The present case describes the treatment and prognosis of an unusual case of dens invaginatus with internal resorption in a maxillary lateral incisor. Endodontic treatment with using Gutta-percha and root canal sealer was considered successful at the 7-year follow-up.