Aim: Aim of the present study was to evaluate the efficacy of post length and post material on the pull-out bond strength of individually formable glass fiber post versus custom made metal post on endodontically treated mandibular premolar teeth. Materials & Methods: Sixty-six extracted human mandibular premolars teeth were endodon­tically treated, they decoronated 2 mm above the cementoenamel junction and randomly divided into two main groups (Group A& B) based on the post materials to be used. Group A: individually formed glass FRC posts (everStick post), Group B: custom made metal post (Ni-Cr). Moreover, samples of each group were divided into 3 subgroups (subgroup 1, 2, 3) (n=22) according to the post length: subgroup I: 14.0 mm; subgroup II: 12.0 mm; subgroup III: 10.0 mm. All of the posts were luted with dual-polymerizing self-adhesive universal resin cement (RelyXUnicem). The sam­ples were subjected to a pull-out bond strength test in a universal testing machine at a crosshead speed of 0.5 mm/min. The results, in newtons, were analyzed with two-way ANOVA and the pair wise Tukey post hoc test (α= .05). Two samples from each group were processed for digital micro­scope observations in order to investigate the mode of failure at the post/cement interface. Results: Two-way ANOVA showed statistically non-significant difference (P>0.05) between cast metal post group (227.77± 42.40 N) and everStick post group (225.15± 23.65N). Moreover, post length with 14mm recorded the highest statistically significant difference (p<0.05) mean value (278.45± 33.81 N) followed by post length 12mm (241.37± 42.74 N) then post length 10mm re­corded the lowest statistically significant difference (p<0.05) mean value (159.57± 17.53 N). Conclusion: It can be concluded that the pull out bond strength (debonding force) is directly proportional to post length