Objective: The purpose of this study is to analyze and compare the colors (A2, A3 and A3.5) of polymerized resin-based composites (RBCs) with respect to the shade numbers within each product line and the VITAPAN Classical® shade guide they purported to represent. Methods: Three A-shades (A2, A3 and A3.5) from four RBC products (Harmonize®, Empress® Direct®, Grandio® and Filtek® 500) were compared within the VITAPAN Classical® shade guide and within their own commercial shade guide. Nine disk-shaped specimens, 6 mm in diameter and 2 mm thick, were prepared for each RBC color (three of each color). The color measurements were made according to the CIE L*a*b* color scale (quantifying L*c*h*a*b* values) using a Vita Easyshade Compact IV® digital spectrophotometer. We calculated the CIEDE2000 color differences between polymerized composites and shade guides, as well as between composites. The values obtained from composites and samples of the color guides in the CIE L*a*b* space were represented by ICC3D software (Version 1.2.9) Results: The ANOVA test verified the existence of statistically significant differences between composites for the same shades (p < 0.05) except for shade A2. CIEDE2000 color differences between composites and the VITAPAN Classical® shade guide ranged from 3.5 to 13.1 depending on the composite and the shade. Conclusions: There were color differences among the polymerized resin-based composites, between these and their own shade guides/manufacturer’s commercial guides, and between the former and the corresponding samples of the VITAPAN Classical® shade guide. Clinical significance: Color selection when performing an aesthetic dental restoration is essential for the clinician and the patient to obtain an optimal result. Taking into account the color difference (∆E00) for each composite with the VITAPAN Classical® shade guide or with the manufacturers’ commercial guide allows for more precision with shade selection in aesthetic dentistry.