INTRODUCTION: The fracture strength of endodontically treated teeth compared to vital ones has long been a source of controversy. It is not clear how root canal therapy affects the stress distribution in teeth. The purpose of this study was to evaluate the changes in stress distribution after root canal therapy in a human maxillary canine by finite element analysis (FEM). MATERIALS AND METHODS: Two 3D FEM models of a maxillary canine were created; one represented a virgin tooth and the other represented the same tooth after root canal therapy. A single force of 14.1 N was applied 45 degrees to horizontal plane to the center of the palatal surface; stress distribution was then analyzed in both models. RESULTS: SEQV (VonMises stress) analysis demonstrated an obvious decrease after root canal therapy and the regions near cementoenamel junction (CEJ) showed the highest displacement. The endodontically treated tooth demonstrated higher deflection than the vital one. CONCLUSION: Maximum stress and displacement was repeatedly found in the cervical area, hence more emphasis should be placed on the reinforcement of this region.