Objectives: To evaluate and compare the color of porcelain veneers with try-in paste in relation to porcelain veneers with permanent cement. Also, to evaluate and compare combinations of three different shades and thicknesses of porcelain veneers and three cement shades before and after final cementation. Additionally, to evaluate and compare the color of porcelain veneers with cured permanent cement before and after aging. Background: Porcelain veneers and ceramic restorations have become one of the most popular approaches in the anterior area due to their natural appearance and esthetics. However, more conservative approaches have led to thinner restorations with increased translucency. A potential drawback to these restorations is that any color change in the luting cement can become clinically visible, and possibly affect esthetic appearance. Methods: One hundred and eight specimens were cut from feldspathic porcelain blocs (Vitablocs Mark II for CEREC). Three different Vita 3D- Master 1M1, 2M2, and 3M1 shades were assessed. All specimens were 12 x 14 mm, with three different thicknesses of 0.3, 0.5, and 1.0 mm. Light-cured resin cement (Variolink Veneer, Ivoclar Vivadent) with three different shades was used. The specimen color alone, with the try-in paste, and with pre-cured and post-cured resin cement was measured using a spectrophotometer (Color Eye 7000A), which measures CIE-L*a*b* values. Specimens were subjected to 30,000 cycles of accelerated aging (Themo-cycling, Sarbi Dental Enterprises Inc.). Color measurement for all specimens was performed again and ∆E values between groups been calculated. Statistical analysis was performed using one-way and three-way ANOVA, with level of significant set at α=0.05, to assess differences between groups. This was followed by post hoc Tukey's tests. Results: Statistical analysis showed a significant difference between try-in paste and corresponding cured resin cement. Pre-cured and post-cured resin cement values showed a significant difference between cement shades. Moreover, statistically significant differences were found between post-cured cement and after 30,000 cycles of thermo-cycling. Conclusions: The final color of porcelain veneers was highly affected by the different shades of resin cement and by the thicknesses of the porcelain veneer. The use of higher ceramic thickness decreased the ∆E values when compared to thinner veneers. Also, color stability of ceramic veneer restorations luted with resin cement, was significantly influenced by the aging.