Objectives:The purpose of the study was to investigate the effect of CAD/CAM ceramic thickness on shade. Methods: 24 disk-shaped ceramic specimens (E.Max CAD & Empress CAD, 12 mm × 12 mm) were prepared and divided into 4 groups (n=6). Ceramic specimens in 2 thicknesses (0.8 mm, 1.0 mm) were made low translucency(LT) shade A2. All specimens were measured as L*, a*, b* using spectrophotometer. The color differences(∆E values) between the specimen and a control target block (12 × 12 × 1.2 mm) were calculated. Two-way ANOVA performed between 2 groups(material and thickness). Results: As the thickness increased, the L* (for all groups) and b* value (for all groups) increased and the a* value(for LR group) decreased. The mean color differences caused by thickness was acceptible (ΔE > 2) for group LD1. But the mean color differences by thickness were not selected (ΔE < 2) for group LD2, LR1, LR2. Conclusions: The different thickness can influence the final color of CAD/CAM ceramic.