Objective: The present study was carried out to evaluate the effect of different bleaching agents on fracture resistance of endodontically treated extracted maxillary central incisors and the effect of an antioxidant along with bleaching agents on the fracture strength of these teeth. Methods: A total of 80 freshly extracted human maxillary central incisors were collected and root canal treatment was done on them. After 24 hours, the gutta-percha was removed to a level just below the labial-gingival margin and a 2 mm layer of resin modified glass ionomer cement was applied. Roots of all the teeth were immersed in autopolymerizing acrylic resin upto the cemento-enamel junction and the bleaching agents and the antioxidant were applied using the walking bleach technique. After that the fracture resistance of the specimens was measured with a Universal Testing Machine and the forces necessary to fracture each tooth were recorded in Newtons. Results: The comparison revealed that the control group, where only the root canal treatment was performed without the application of the bleaching agents and antioxidant had the highest mean value of fracture resistance. Group-1, where 30% hydrogen peroxide and sodium perborate (tetrahydrate) were used as bleaching agents had the lowest mean value of fracture resistance. Conclusion: It was concluded that hydrogen peroxide 30% and sodium perborate cause the lowest resistance to fracture as compared to 45% carbamide peroxide and sodium ascorbate 10% solution can reverse the effects of a decrease in the fracture resistance.