The aim of this study was to examine the effect of genotype in a total of twelve varieties with purple- and red-fleshed tubers on the content of important antioxidants - total polyphenols (TP), ascorbic acid (AA) and total anthocyanins (TA). Precise field experiments were performed in 2008 and 2009 in the Czech Republic. Genotype of the variety showed a significant influence on the contents of the TP, AA and TA. Purple- and red-fleshed varieties reached 2.7 to 3.8 times higher content of the TP in comparison with control yellow-fleshed variety, difference between them has a maximum of 16.8%. The highest AA content in the group of the varieties with colored pulp showed the Highland Burgundy Red variety (233 mg·kg⁻¹ FM), which with other two varieties matched the yellow-fleshed control, for other varieties a decrease of 18.5 to 28.0% was demonstrated. The TA content varied in a wide range from 68.7 to 573.5 mg cyanidin·kg⁻¹ FM and corresponded with the intensity and color range of light-marbled flesh of tubers of each variety.