Aim: To assess the contribution of resin tags in the interfacial bond strength of self-adhesive cement used to lute fiber posts into root canals.Methodology: Twenty extracted human canine teeth were selected and root filled. Roots were randomly assigned into two groups (n=10) according to pre-treatment of root dentin: non-etched (G1) or etched using 37% phosphoric acid (G2). Glass fiber posts (White Post) were luted into the root canals using the self-adhesive cement RelyX TM UniChem. Before insertion of the post, the cement was labeled with Rhodamine B isothiocyanate. Roots were sectioned transversally into slices of 1.5 mm thickness to perform the tests at the coronal, middle and apical regions of the root canal. Each slice was analyzed using confocal laser scanning microscopy to determine the presence or absence of resin tags, and then, subjected to a push-out test. Bond strengths data (MPa) were analyzed by Student t-test (α=0.05). Results:The qualitative analysis of the post-dentin interface revealed that was not possible to observe the formation of resin tags into the root dentin in G1, whereas all slices belonging to G2 exhibited the presence of resin tags. For the push-out test, there were no significant differences between G1 (10.5 ± 3.53) and G2 (10.61 ± 3.84) groups (p<0.05) in all root canal regions. Conclusions:Resin tags, as a result of root dentin etching, did not affect the push-out bond strength of fiber posts to root canals when using the self-adhesive cement RelyX TM Uni Cem.