The aim of the study was to determine the effect of pasteurization and storage conditions of black chokeberry juice concentrate solutions on their antioxidant activity. The study investigated the effect of solution pH (3-5), temperature (10-30°C) and storage time (0-20 days), as well as oxygen availability. Solutions were obtained by diluting concentrate with buffers according to McIlvaine to anthocyanin contents of 20 mg%. They were next pasteurized and stored in the dark under conditions specified in the experimental design. Antioxidant activity was determined colorimetrically using the cation-radical of 2’2-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid) (ABTS). Antioxidant activity decreased in all samples, both after pasteurization and after storage. The biggest effect on the lowering of antioxidant activity was found for oxygen availability rate during pasteurization and storage, and for storage temperature