The aim of the study was to investigate the influence of diversified fertilization with NPK on total antioxidant capability of soil and of leaves of two Polish varieties of Amaranthus (Rawa and Aztec) in wide-row cultivation. Three doses of NPK were used: I) nitrogen 50 kg ha-1, phosphorus 40 kg ha-1, potassium 40 kg ha-1; II) nitrogen 90 kg ha-1, phosphorus 60 kg ha-1, potassium 60 kg ha-1; III ) nitrogen 130 kg ha-1, phosphorus 70 kg ha-1, potassium 70 kg ha-1. The factors determined included the antioxidant capabilities (TAC) of soil and of amaranthus leaves, with Rice-Evans and Miller method in Bartosz modification, and the content of organic carbon in the soil. On the basis of statistical analysis significant correlations were observed between TAC of soils, leaves, and content of organic coal in soil and applied level of fertilization. An increase of total antioxidant capability of the soil under amaranthus Rawa was influenced by the lowest (combination I) dose of fertilization, and in the case of Aztec the highest level of fertilization (combination III of NPK). Fertilization with doses I and III of NPK produced an increase of total antioxidant capability of leaves of Rawa, and dose III boosted the increase of total antioxidant capability of leaves of Aztec.