In the experiment yield potential and antioxidant activity (AOA) of 13 potato cultivars with different flesh colour (purple (p); red (r); yellow (y) and white (w)) were evaluated at two localities with different environmental conditions in three years 2009-2011. Yield potential was evaluated at harvest time in physiological maturity of crop stand. The results confirm that total yield and yield of tubers > 40 mm of coloured potatoes cvs. Red Emmalie/r (68.98 t/ha), Blaue Elise/p (59.96 t/ha), Valfi/p (53.72 t/ha) were comparable with control cvs. Agria/y, Lady Balfour/w and Russet Burbank/w. Some cultivars with lower yield had share of tubers above 40 mm comparable with control cultivars (94.45% and 93.48% in case of cvs. Valfi/p and Blue Congo/p), respectively. Antioxidant activity was determined as ascorbic acid equivalent by ABTS (2,2´-azinobis (3-ethylbenzothiazoline-6-sulfonate) method. The lowest antioxidant activity was observed in the control cvs. Lady Balfour/w (ascorbic acid equivalent (AAE) 74.1 mg/kg fresh mattter (FM)), Agria/y (AAE 84.4 mg/kg FM) and Russet Burbank (AAE 93.9 mg/kg FM). In the group of cultivars with red flesh AOA was 3.2 to 5.1 times higher and in a group of purple-fleshed cultivars it was from 3.7 to 7.0 times higher.