This in vitro study was conducted to compare the effect of three different veneering techniques on the marginal accuracy and fracture resistance of zirconia restorations, In addition to studying the effect of coping design on the same two previous variables.A stainless steel die simulating a prepared mandibular first molar was machine milled with convergence angle 6 ˚, with cusp angle 135 ˚, 1 mm finish line thickness and anatomic occlusal surface.According to sample size calculation a total of forty two Zirconia crowns were constructed by CAD/CAM technology and divided into two equal groups according to coping design and six equal sub-groups according to veneering technique used:Group A: zirconia collar crowns(21 crowns) Sub-group AI: veneering by layering technique (n=7).Sub-group AII: veneering by press on technique (n=7). Sub-group AIII: veneering with bi-layering technique (n=7)Group B:zirconia collar less crowns(21 crowns)Sub-group BI: veneering by layering technique (n=7).Sub-group BII: veneering by press on technique (n=7). Sub-group BIII: veneering with bi-layering technique (n=7).e-maxceram mix was applied to the zirconia copings and fired then glazed In the layering veneering technique.In the press on veneering technique a specially constructed CAD wax was milled corresponding to each zirconia coping. This CAD wax was sprued, invested , preheated and pressed in the furnace.While, in the bi-layering technique the same steps of press on were done except for application of e-max ceram layering ceramic in the cut back area. After veneering the zirconia crowns marginal gap was evaluated on the stainless steel die using a digital microscope. Then the stainless steel die was duplicated into forty two epoxy resin dies. The zirconia crowns were cemented on the epoxy resin dies using self-adhesive resin cement. The fracture resistance of the restorations was measured using material testing machine with load of 5 kNand at a cross head speed of 1mm/min.The obtained data were collected, tabulated and statistically analysed.Marginal gap results showed that best group was zirconia collar veneered with bi-layering technique followed by zirconia collar less crowns veneered with layering technique While, the worst was zirconia collar less crowns veneered with press on technique.Regarding fracture resistance results showed that zirconia collar crowns veneered with layering technique had the highest fracture resistance values followed by zirconia collar crowns veneered with press on, followed by zirconia collar less veneered with press on, then zirconia collar less veneered with layering, zirconia shoulder less veneered with bi-layering while the least was zirconia collar with bi-layering.