Abstract INTRODUCTION: The incidence of atherosclerosis increases with age, as do various indices of free-radical-mediated damage, e.g. lipid peroxidation. Because Antioxidant enzymes are the major defense system of cells in normal aerobic reactions, we aimed to assess the age-related alterations in the activity of erythrocyte cytoprotective enzymes among women. methods: One hundred sixty 20-45-year-old women were randomly selected among women receiving the services of rural health centers of Kerman Province, Iran. Data were gathered by using questionnaires and face-to-face interviews. We assessed lipid peroxidation by measuring the concentrations of plasma malondialdehyde (MDA), total antioxidant capacity (TAC), and the activities of erythrocyte copper-zinc superoxide dismutase (CuZn-SOD), glutathione peroxidase (GPX) and catalase (CAT). results: Those individuals in the highest quartiles of age and number of pregnancies presented the highest levels of plasma MDA (P<0.001). We also observed an inverse relationship between age and erythrocyte CuZn-SOD and GPX activities. Although we found no significant difference between age groups in respect of erythrocyte CAT activity and/or plasma TAC levels, erythrocyte GPX activity was negatively correlated with the number of pregnancies (P<0.001) . No significant difference was found between age groups and/or between quartiles of number of pregnancies for either energy or nutrient intake. Plasma MDA levels were positively related to age (r=0.307; P<0.0001), number of pregnancies (r=0.250; P<0.001), fat intake (r=0.281; P<0.05) and Vitamin E intake (r=0.356; P<0.01). Furthermore, there were negative correlations both between age and GPX activity (r= -0.280; P<0.0001) as well as with CuZn-SOD(r= -0.228; P<0.005). CONCLUSIONS: Lipid peroxidation and antioxidants were affected by age. Erythrocyte cytoprotective enzymes have an important role in detoxification of free radicals in the body; the age-related decrease in the activities of these enzymes might contribute to atherogenesis, along with classic risk factors. Keywords: Age, lipid peroxidation, cytoprotective enzymes, oxidative stress, women.