Objective: This study aimed to investigate the influence of the pattern of occlusal Reduction and marginal configuration on the fracture resistance and marginal discrepancy of all ceramic crowns. Materials and methods: Four stainless steel metal dies representing a prepared mandibular first molar were machine crafted; anatomical occlusal plane with chamfer finish line, anatomical occlusal plane with shoulder finish line, two plane with chamfer finish line and two plane with shoulder finish line. Each metal diewas further duplicated producing five epoxy dies. For each design a total of 20 ceramic copings. Results: for marginal gap data before and after cementation paired t-test was used to compare between mean gap distance before and after cementation with each group. While for fracture resistance test data were explored for normality using Kolmogorov-Smirnov test, showing no clinical significance between all groups. Conclusion: 1.Machinable CAD/CAM system showed marginal gap values lies within the acceptable ranges. 2. Deep Chamfer Finish line is an appropriate choice regardless the type of occlusal scheme, Concerning marginal adaptation. 3.Different finish line designs had no influence on the fracture resistance.