Macroangiopathy was associated with significantly higher frequency of C allele in SOD1 gene (0,58 in MA group vs. 0,42 in DM group without complications, p < 0,01), lower frequency of C alelle (Ala) in SOD2 gene (0,28 in MA group vs. 0,39 in DM group without vascular complications, p < 0,05) whereas no such distribution was found in CAT gene, p = 0,594. The gene discussed is CAT; the disease is diabetes mellitus.