The study shows that deep chamfer finishing line provided more accurate seating of full contour CAD/CAM zirconia crown restorations rather than the shoulder finishing line, when using planar occlusal reduction scheme as it provided better marginal fit than shoulder finishing line. On the other hand, shoulder finishing line provided better marginal fit than the chamfer one, when using flat occlusal reduction scheme. Concerning the effect of the cementation procedure, the marginal gap was increased post-cementation as compared with the pre-cementation gap for all subgroups, but still within the clinically acceptable limit. However, there is no available research dealing with the effect of finishing line designs in combination with different occlusal reduction schemes on the marginal fit of full contour zirconia crowns.