Objectives: To investigate the push-out bond strengths of one epoxy resin-based quartz-fiber post with four adhesive systems. Method and Materials: Forty-four single-rooted, single-canal teeth were randomly divided into four groups (n = 11): One-step (One-Step + Duo-link; Bisco), Variolink II (Excite DSC + Variolink II; Ivoclar Vivadent), Panavia F (ED primer + Panavia F; Kuraray), and RelyX (RelyX Unicem; 3M ESPE). All teeth crowns were removed, and the roots were treated with root canal therapy. Four adhesive systems were employed for bonding of one type of quartz-fiber post, strictly according to the manufacturers' instructions. Ten roots in each group were transversely sectioned into cervical, middle, and apical third slices 2 mm thick, and the bond strengths were measured with the push-out test. The other root was processed for SEM analysis. Two-way ANOVA, one-way ANOVA, and Student-Newman-Keuls test were used for statistical analysis. Results: The push-out bond strengths were 7.15 ± 3.43 MPa (RelyX), 12.48 ± 9.33 MPa (One-step), 2.96 ± 2.76 MPa (Panavia F), and 13.43 ± 6.14 MPa (Variolink II). Two-way ANOVA showed statistically significant differences among adhesive systems (P .05) and root regions (P .05). The bond strengths of One-step and Variolink II groups were statistically higher than those of RelyX and Panavia F groups. The bond strengths of the cervical region of One-step and Panavia F groups were statistically significantly higher than those of the other two regions. The SEM images showed uniform and long resin tags in One-step and Variolink II groups, whereas few or no resin tags were visible in the other two groups. Conclusion: The type of adhesive system and root region had a significant influence on the bond strengths of the adhesively luted fiber posts. Total-etching technique achieved better bond strength than did the self-etching technique. Keywords: adhesive system, bond strength, fiber post, push-out test, root dentin, self-etching, SEM observation, total etching