This study aimed to determine the total antioxidant status (TAS) and total oxidant status (TOS) of the novel highprotein milk-products, which were designed to be protein-rich, lactose-free and reduced-fat milk-based. All different flavoured milk products with varying concentration of protein (52-82 g.l(-1)) of various brands were included. TAS and TOS were measured and oxidative stress indices (OSI) were calculated. Both TAS and TOS values of high-protein milk products with different aromas were found to be higher than conventional cows' milks (p < 0.05). However, the TOS values of high-protein milk-products with vitamin addition appeared to be lower compared to milk with the same flavour but higher protein concentration (p < 0.05). OSI value of peanut-banana-flavoured milk containing 52 g.l(-1) protein with B-complex vitamins and l-carnitine was 6.05 +/- 1.05. However, the OSI value of coffee-flavoured milk product containing 76 g.l(-1) protein with vitamin B complex and vitamin D was the lowest with a value of 1.36 +/- 0.05. In conclusion, this study determined that the antioxidant and oxidant capacities of high-protein milk products vary according to the brand, flavour, polyphenol concentration and, in some cases, depend on vitamin concentration. Vitamins for improvement of exercise performance and beta-oxidation in exercise may also have a beneficial effect on oxidative stress, but the key-point seems to be their combination with components rich in polyphenols in milk-products.