Aim:The aim of this study was to investigate the effect of two different abutments height (4mm preparation height and 5mm preparation height) and two adhesive cements (total etch adhesive resin cement and selfadhesive resin cement) on the retention of zirconia all ceramic crowns.Materials and Methods: Twenty intact human lower molars were used; teeth were divided into two main groups according to the preparation height, each of (10) samples. Each group was further subdivided into two subgroups according to the type of resin cement, each of (5) samples. Standardized tooth preparation was carried out by engineering lathe to have: convergence angle of 10 degree, flat occlusal reduction and1mm deep chamfer finish line. Two occluso-gingival heights were prepared, 4mm and 5mm. Copings were fabricated according to manufacturer's instructions using Ice zirconia blocks. Milling was carried out by copy milling Zircon-zhan machine. Milled copings were cemented to the prepared teeth using RelyX ARC total etch and Smart Cem2 adhesive resin cement. All samples were then tested for tensile bond strength.Results: Independent t-test revealed that, statically insignificant differencebetween the (4mm preparation height and Rely X ARC total etchadhesive resin cement) group (4.93 MPa ± 0.44), and (5mm preparationheight with Rely X ARC total etch adhesive resin cement) (4.89 MPa ±0.28) group. While a statically significant difference was found betweenthe (4mm preparation height and Rely X ARC total etch adhesive resincement) group (4.93 MPa ± 0.44) and the (4mm preparation height andSmart Cem2 self-adhesive resin cement) group, that recorded a value of(4.21 MPa ± 0.23). On the other hand the use of (5mm preparation heightwith Smart Cem2 self-adhesive resin cement) produced the lowersignificant tensile bond strength values (3.68 MPa ± 0.15) compared tothe (4mm preparation height with Smart Cem2 self-adhesive resincement) group (4.21 MPa ± 0.23).Conclusion: The retentive strength of zirconia all ceramic copings is notinfluenced by preparation height when total etch adhesive resin cement isused, while when self-adhesive resin cement is used the 4.0 mmpreparation height yielded higher retentive strength.