Aim: This in-vitro study was conducted to assess the fracture resistance (FR) of different post and core systems for restoring pulpectomized primary incisors. Materials and methods: Forty extracted primary incisors were collected, prepared, and then obturated using Metapex. Teeth were allocated into four groups. Group (A): teeth restored with human dentin posts; Group (B): bovine dentin posts; Group (C): glass fiber posts; and Group (D): orthodontic stainless-steel wire in omega-form posts. Dentin blocks were obtained from the roots of extracted human maxillary premolars and bovine permanent incisors to fabricate the dentin posts. These blocks were formed into post shapes using a Computer Numerical Control (CNC) machine. The posts underwent cementation using glass ionomer cement, followed by coronal buildup with composite. After thermocycling, the FR and mode of failure were examined. The FR was analyzed using the Kruskal-Wallis test, while the mode of failure was analyzed using the Monte Carlo test. P-values ≤ 0.05 were used to determine statistical significance. Results: The median maximum compressive load in group (A) was 386.87 N, in group (B) it was 379.27 N, in group (C) it was 522.16 N, and in group (D) it was 469.14 N. The differences between the groups were not statistically significant regarding the maximum compressive load and the failure mode. Conclusion: Glass fiber posts and omega posts had higher FR compared to dentin posts, although the four groups can be used effectively for restoring pulpectomized primary incisors.