The purpose of this study was to investigate the effect of light exposure and decontamination protocols on the color stability of denture shade guide tabs. Fifty tabs for shades 62, 66, and 69 (Biotone IPN, Dentsply Sirona) were submitted to baseline L*a*b* measurements (EasyShade, Vita), separated into 5 experimental groups (n=10), and subjected to one of the following conditions: G1-distilled water (DW-H2O)-control; G2 -70% alcohol; G3-sodium hypochlorite 1% (NaClO); G4-no light exposure; G5-natural light exposure for 6 months. The experimental conditions were designed to simulate 6 months of clinical use. After the test period, final color measurements were recorded. The mean tristimulus coordinate difference (Delta L*,Delta a*,Delta b*) and total color difference values (Delta E-ab) were analyzed using 2-way ANOVA and the Tukey test, =.05. G2 (alcohol) produced less (P<.05) color change in shade 69 than G3 (NaClO). G5 (light exposure) affected the color stability for all shades, producing a statistical difference (P<.05) from G4 (no light exposure). It was concluded that natural light changes the color stability of the shade guides and that decontamination with 70% alcohol had the least impact on the color stability of the shade guide tabs.