Levels of MDA and H2O2 were increased and antioxidants;SOD, Cat, GPx, vit. C levels were decreased in men with varicocele of all grades (I, II, III) compared with the controls;Men with grade II and III varicocele demonstrated higher MDA and H2O2 levels as well as decreased activities of SOD, Cat, GPx, and levels of vit. C compared with men with grade I varicocele. This evidence concerns the gene SOD1 and varicocele.