Aim: To evaluate the effect of different intra orifice barrier materials on fracture resistance of endodontically treated teeth and to determine which amongst them is best suitable. Materials and Method: 45 mandibular premolars were decoronated to a standardized length, prepared and obturated with gutta–percha and AH Plus sealer. Except for control group, the coronal 3–mm gutta–percha was removed and filled with RMGIC and Biodentine. Fracture resistance of the specimens was tested. Result: Fracture resistance of roots was affected significantly by the type of IOB used and the following pattern was observed: RMGIC > Biodentine > Control Group. Conclusion: Presence of IOB increases the fracture resistance of endodontically treated teeth as compared to teeth without IOB. RMGIC showed the maximum reinforcement.