• Modern LED sources produce changes in color and whiteness of natural teeth. • Some LED illuminants recommended by CIE generate perceptible color shifts. • LED illuminants produce color shifts in very different directions of color space. • Color differences for pairs of teeth are almost independent of illuminants. • Whiteness differences for pairs of teeth are almost independent of illuminants. To evaluate color and whiteness changes of natural teeth under nine white LED illuminants recently proposed by CIE. From spectral reflectance factors of 36 caries-free upper central incisors, corresponding colors under illuminant D65 and CIE 1931 standard colorimetric observer were computed for all tested illuminants, using the chromatic adaptation transform CAT16. Color differences (CIELAB and CIEDE2000 units) and whiteness (W I D and W I O indices) from teeth illuminated by CIE standard illuminants (D65 and A) and white LED illuminants were calculated. The appearance of 630 pairs of teeth under all illuminants was also evaluated. Color gamuts from 36 teeth under tested illuminants showed similar volume and shape in CIELAB color space, but their centers of gravity changed in many different directions with respect to colors under D65 or A illuminants: Considering colors under D65/A, color shifts produced by white LED illuminants were in the ranges 2.0–8.6/1.1–7.0 CIELAB units (1.4–8.2/0.6–6.8 CIEDE2000 units). Average W I D and W I O values for the 36 teeth under different illuminants ranged from −5.8 to +19.3 and from −7.7 to +11.1, respectively. Considering 630 pairs of teeth, average color differences (mainly lightness differences) were below 0.5 CIELAB units (0.3 CIEDE2000 units), and average whiteness differences ranged from 8.1 to 10.7 for W I D (23.4–25.1 for W I O). Using CIE LED illuminants, most changes in color and whiteness for individual teeth were above typical threshold values of perceptibility and acceptability in dentistry. However, considering pairs of teeth, the average color and whiteness differences under all tested illuminants were very similar. [ABSTRACT FROM AUTHOR]