Aim:To evaluate and compare the marginal fi t of crowns fabricated by three All Ceramic CAD-CAM systems using their respective scanners.Objectives:1.To evaluate the marginal fi t of All Ceramic crowns fabricated using Contact scanner-Procera system. 2. To evaluate the marginal fi t of All Ceramic crowns fabricated using Optical scanner-Lava system. 3.To evaluate the marginal fi t of All Ceramic crowns fabricated using Laser scanner-Cercon system . 4.To compare the marginal fi t of crowns fabricated by three All Ceramic CAD-CAM systems using their respective scanner-Contact scanner, Optical scanner and Laser scanner. Materials and Methods:5 crowns fabricated with Contact scanner-Procera system (Group I), 5 crowns fabricated with Optical scanner-Lava system (Group II), 5 crowns fabricated with Laser scanner-Cercon system(Group III). The marginal fi t would be evaluated at two stages for each group:A-Pre-veneering stage (coping) B-Post-veneering stage (crown). Results: The mean value of marginal gap with Group IA was 27.48 +2.63 and IB was 26.13+ 0.85 and that of Group IIA was 23.27 + 0.99 and IIB 19.22 + 0.88. The mean value of marginal gap of Group IIIA was 32.80 + 2.46 and IIIB was 28.77 + 1.94. Conclusion: The marginal gap was maximum with Group III and minimum with group II amongst the three used systems. The mean marginal gap values of subgroup B were less than subgroup A.