Aim of the study: The aim of the present study was to evaluate the effect of two different surface treatments (CO2 laser and silica coating) on bond strength between Y-TZP zirconia and Rely-X Unicem adhesive resin cement.Materials and Methods: A total of 30 zirconium oxide discs were produced to act as 15 twin samples. The samples were divided into three groups according to type of surface treatment used as follows: (1) Laser irradiation by CO2 laser, (2) Silica coating, (3) sandblasting. Each two similarly treated samples were cemented together by using Rely-x Unicem resin cement, in order to obtain five twin samples in each group.All the samples were subjected to thermocycling for 6000 cycles between 5 and 55Co. The shear bond strength of luting cement to ceramics was measured in a universal testing machine.Results: The results showed that Sandblasting group showed the statistically significantly highest mean shear bond strength. There was no statistically significant difference between CO2 Laser and cojet groups; both showed the statistically significantly lowest mean shear bond strength values.Conclusion: Sandblasting group gave the highest shear bond strength in comparison to other groups. Surface roughness was obtained by CO2 lasing of the zirconia surface and silica coating, was not sufficient to enhance the shear bond strength.