The purpose of this study: was to evaluate the effect of carbon dioxide irradiation and silica coating surface treatments of In-ceram and zirconia cores on their surface roughness and shear bond strength to natural teeth .Materials and Methods : Thirty all samples were fabricated and divided into two groups; Group (1): Zirconia core samples(n=15). Group (2): In-ceram core samples (n=15). Each group was subdivided into three Subgroup; (A): Samples treated with Co2 irradiation (n=5). (B): Samples were sandblasted by SC (n=5).(C): control group, samples were sandblasted by AL2 O3 (n=5) . All samples were bonded to extracted teeth surfaces using adhesive resin cement. Shear bond strength values (MPa) were calculated and debonded core surfaces were examined.Results : Shear bond was significantly affected by surface treatment and type of ceramic which the highest bond strength values (MPa) were achieved by SC, followed by Laser irradiated , finally sandblasting had the lowest bond values .In-ceram showed statistically significantly higher mean Ra values than Zirconia .Conclusions: CO2 laser and SC surface treatment of Y-TZP and In-ceram core surfaces improved core/ teeth bond strength.