Introduction: Aim of this study was to evaluate color stability of two different types of bulk-fill composite resin and CAD/CAM hybrid ceramic materials after thermal ageing. Methods: 12 samples from Tetric-N-Ceram Bulk-Fill and Estelite Bulk-Fill Flow with 4-mm thickness 10-mm diameter were prepared in a teflon mould. Prepared samples were polished with discs from coarse-to-fine(10sec).12 samples from Vita-Enamic and Shofu- Block-HC were prepared with a microtome device. CAD/CAM blocks were polished with silicone abrasive papers. CAD/CAM samples were standardised in 4.0±0.1mm thickness with digital micrometer. Initial color measurements were taken with a spectrophotometer according to CIE-L*a*b*color system. All samples were put in a thermal cycle device, aged with 10000 cycles. Final color measurements were recorded after the thermal cycle procedure. The color change(ΔE) was calculated. To state the relationship between color change and clinical environment, data were transformed to National-Bureau of Standards(NBS). For statistical analysis Mann-Whitney-U Test with Bonferroni Correction were used with 0.008 degree of signifance. Results: According to the statistical evaluation, Vita-Enamic CAD/CAM hybrid ceramic material showed the highest color-stability when compared with other materials. Tetric-N-Ceram Bulk-fill composite resin was evaluated the lowest color-stability material(p<0.008). Discussion and Conclusion: In a matter of color-stability based materials, ceramic content, size and ratio of inorganic filler particles, structure of organic resin matrix could be concluded that determinative.