Oxidative stress interferes with oviduct functions including oocyte maturation, capacitation, fertilization, and embryo and gamete transport. This study aimed to determine activity of the antioxidants glutathione peroxidase (GPX-I), superoxide dismutase (SOD), and catalase (CAT) in bovine oviduct epithelial cells (BOEC) isolated from the isthmus and ampulla of the oviduct at estral (n = 7) and luteal phases (n = 7) of the estrous cycle. The antioxidant activity was measured at the primary, first, and second passages of the cell culture, and was characterized by cytokeratin expression. The GPX activity increased over the passages in samples of the ampulla and the isthmus of each sexual phase without statistical significance. The SOD activity remained steady through the cell passages in both sexual phases. CAT activity at the primary culture was higher in the ampulla compared to the isthmus in both sexual phases with a significant difference for the estral phase (P