Introduction: Fiber posts and cores are usually used for the restoration of endodontically treated teeth with extensive coronal destruction. The most common cause of failure of fiber posts is debonding at the adhesive resin-dentin interface due to bond deficiency. Aim of the study: The purpose of this In-vitro study was to evaluate the effect of different dentin surface treatments including self-etch adhesive system, Er,Cr:YSGG laser irradiation and self-etch adhesive system after Er,Cr:YSGG laser irradiation on the push out bond strength of fiber posts to radicular dentin. Materials and Methods:The coronal portions of fifteen maxillary central incisors were cut till CEJ, the roots were endodontically treated and posts spaces were prepared. The roots were divided according to the dentin surface treatment method used into three groups (n= 5): group A: Optibond XTR self-etching adhesive system. Group B: Er,Cr:YSGG laser irradiation with output power of 2W, a repetition rate of 20Hz and water / air flow (80/60%). Group C: Er,Cr:YSGG laser irradiation with output power of 2W, a repetition rate of 20Hz and water / air flow (80/60%) followed by self-etching adhesive system (Optibond XTR). Dentoclic glass fiber posts were cemented, then each root was sectioned horizontally into three sections. Push out test was performed using a universal testing machine at a crosshead speed of 0.5 mm/min until failure. Results: There was a significant difference in the mean push out bond strength among different groups (p<0.001). The highest push out bond strength value was found in group A followed by group C, while the lowest bond strength value was found in group B. Conclusion: Optibond XTR self-etch adhesive system seemed to be an effective approach for fiber posts cementation.