This study compares the color stability of dental reinforced computer-aided design/computer-aided manufacturing (CAD/CAM) hybrid composite blocks to that of regular blocks. One hundred fifty disc-type specimens (n = 15) were prepared from five sets of hybrid composite blocks (Cerasmart-200/Cerasmart-300, KZR-CAD HR/KZR-CAD HR3, Estelite Block/ Estelite-P Block, Avencia Block/Avencia-P Block, Mazic Duro/Duro Ace). The specimen color and translucency parameter (TP) were assessed using a spectrophotometer before and after immersion in staining solutions (water, 10% ethanol, simulated red wine). Changes in color (ΔE) and translucency (ΔTP) of specimens were calculated. The data were analyzed using the analysis of variance (ANOVA) and Tukey’s post hoc test (p < 0.05). Microstructural features of the hybrid composite blocks were also examined using FE-SEM. Immersion in deionized water or 10% ethanol made no significant color or translucency changes (except for Avencia-P Block); however, the simulated red wine caused significant changes to the color and translucency of almost all specimens, especially after 4 weeks of immersion. The reinforced hybrid blocks (except for Estelite-P Block and Duro Ace) showed lower color stability than corresponding regular blocks. Avencia-P Block showed significantly reduced color stability compared to Avencia Block. Even in deionized water and 10% ethanol, Avencia-P Block showed perceptible ΔE and decreased translucency. Estelite Block/ Estelite-P Block and Mazic Duro/Duro Ace showed better color stability than the other materials tested.