The aim of this study was to evaluate the effect of three post-surface treatments on flexural properties of fiber posts. Three types of posts were selected (n = 88 per post type). Four groups of specimens were prepared for each different post (n = 22). For the control group, posts were used as supplied by the manufacturers. Silanization, hydrofluoric etching, and sandblasting with 50 microm Al(2)O(3) were performed on post surfaces for each of the other groups. Two posts of each group were submitted to a qualitative scanning electron microscopy (SEM) analysis. Remaining specimens were positioned in a universal testing machine and a three-point bending test was conducted (n = 20) until fracturing of the posts. Flexural strengths and flexural modules were calculated and recorded. None of the surface pretreatments had a significant influence on the tested properties of the posts (p > 0.05). Visual analysis of SEM micrographs showed significant changes of post surfaces determined by each conditioning treatment, which could increase post-retentive properties.