Internal resorption is a relatively rare resorption of dentine, which starts in the pulpal cavity either in the pulpal chamber or in the root canal and destroys surrounding dental hard tissues. The initiating factor in internal root resorption is thought to be trauma or chronic pulpal inflammation, but other aetiological factors have also been suggested. The prognosis for treatment of small lesions of internal resorption is good. However, if the tooth structure is greatly weakened and perforation has occurred, the prognosis is poor and tooth extraction must be considered. In this article we report a rare case of internal resorption in a 26-year-old male patient.