Objective: The aim of this study was to evaluate the effect of different surface treatments on retention and microleakage of fiber reinforced composite (FRC) posts. Material and methods: 60 intact maxillary canines were divided into 6 main groups (n=10) according to the fiber reinforced composite post surface treatment (Relyx fiber post, 3M ESPE). In each group, five teeth were used for evaluation of retention and the other five were used for evaluation of microleakage. Group I; untreated posts (control group). Group II; posts were treated with silane coupling agent. Group III; posts were subjected to acid etching. Group IV; posts were subjected to airborne-particle abrasion. Group V; Posts were subjected to acid etching and silane application. Group VI; posts were subjected to airborne-particle abrasion and silane application. For each of the prescribed groups, one post sample was added for scanning electron microscope analysis. All posts were cemented using self adhesive resin cement (RelyX Unicem, 3M ESPE, USA). All samples were then thermocycled. Samples used for evaluation of retention were sectioned into 1mm thick slices and subjected to push out test. Microleakage examination was carried out by the dye penetration technique. Data were recorded, tabulated and statistically analyzed. Results: One-way Analysis of Variance (ANOVA) was used for comparison between mean push out bond strength and mean dye penetration (microleakage) in the six groups. FRC post surface treatment showed statistically significant effect on the bond strength, the significance level was set at p<0.05. The results revealed that both group V and group IV showed the highest statistical mean bond strength values (17.1and 15.6 MPa, respectively) followed by group III (13.7 MPa). This was followed by group VI and group II (10.5 and10.2 MPa, respectively).Group I showed the least statistical mean bond strength value (7.4 MPa). Concerning microleakage results, group I (control group) had the highest statistical mean value of dye penetration (4.83mm), followed by group II and group VI (2.70 and2.31 mm, respectively). This was followed by group III (1.96mm). Group IV and groupV showed the least mean values of dye penetration (1.48 and 1.22mm). Conclusion: Surface treatment of fiber reinforced composite posts has significant effect on retention and microleakage. Silane application alone and after surface treatments improved the FRC post retention and decreased the microleakage more than untreated post.