Antioxidant activity of red-, purple- and yellow-fleshed potato varieties by the ABTS, DPPH and FRAP methods was investigated. Purple- and red-fleshed potatoes showed 1.5–2.6 times higher antioxidant activity compared with the yellow-fleshed ones. However, the choice of matrix in which antioxidant activity was determined affected the obtained results. Significant differences between varieties and the localities on which the potatoes were cultivated were determined. The highest linear correlation between ABTS and FRAP arrays was found (R²=0.94); these arrays appear to be useful for the determination of antioxidant activity of potatoes. Statistically significant differences between the antioxidant activity of lyophilizate and juice of fresh potato tubers were found in some varieties.