Colostrum and mature human milk are rich sources of nutrients and contain biologically active molecules that are essential for specific antioxidant functions. The aim of the present study was to determine the activity of copper, zinc superoxide dismutase (CuZnSOD) and manganese superoxide dismutase (MnSOD) activity in different phases of lactation. Specific enzyme activity was determined in colostral milk (3rd-5th days after delivery), and in mature milk in the third week (15-20 days), and the fourth and seventh months of lactation. In the third week of lactation, the activity of CuZnSOD and MnSOD was significantly higher in comparison to the colostral phase. In the fourth month of lactation, the activity of both enzymes was suppressed, while in the seventh month of lactation the MnSOD activity was increased, and the CuZnSOD activity was not significantly changed. These findings show that the activities of superoxide dismutases significantly change during different phases of lactation.