PURPOSE. The aim of this study was to evaluate whether the push-out bond strength varies between oval and circular fiber posts, and to examine the effect on the resin cement thicknesses around the posts. MATERIALS AND METHODS. Eighteen mandibular premolar roots were separated into two groups for oval and circular fiber posts systems. Post spaces were prepared and fiber posts were luted to the post spaces. Roots were cut horizontally to produce 1-mm-thick specimens. Resin cement thicknesses were determined with a metallographic optical microscope and push-out tests were done. RESULTS. No significant differences were observed in terms of push-out bond strength between the oval and circular fiber posts (P>.05) The resin cement thicknesses of the oval posts were greater than those of the circular posts group in the corona!, middle and apical specimens (P<.05). CONCLUSION. In the light of these results, it can be stated that resin cement thickness does not affect the push-out bond strength.