Objectives: This study evaluated, in vitro, the fracture resistance of bovine roots restored with five different intraradicular post systems. Method and materials: Seventy-five bovine roots of similar dimensions were assigned to five groups (n = 15), according to the intraradicular post system used: cast post and core; titanium post; carbon-fiber post; glass-fiber post; and zirconium-oxide post. Following post cementation, the roots were embedded in polystyrene resin composite and submitted to fracture- resistance testing, with a compressive load at an angle of 135 degrees in relation to the long axis of the root at a speed of 0.5 mm/min. All data were statistically analyzed with analysis of variance and Sidak test. Results: The titanium posts presented higher mean values of fracture resistance when compared to glass-fiber posts and zirconium-oxide posts and similar values compared to carbon-fiber posts. Also, roots treated with cast posts and cores presented similar results when compared to roots treated with prefabricated posts. Conclusion: All prefabricated intraradicular post systems evaluated presented similar resistance to fracture when compared to cast posts and cores, and among the prefabricated ones, titanium and carbonfiber posts could be best indicated.358612616