Oxidative stress often occurs in chronic hemodialysis (HD). The aim of the present study was to determine plasma malondialdehyde (MDA) level for lipid peroxidation product and erythrocyte superoxide dismutase (SOD) and glutathione peroxidase (GPx) activities as enzymatic antioxidants. Thirty-one HD patients (aged 50.3 ± 14.9 years) who were dialyzed three times per week and 31 healthy subjects (aged 47.8 ± 13.9 years) were enrolled. The results showed lower enzymatic antioxidants activity (GPx, SOD) and higher MDA levels in comparison with control subjects. In addition, SOD and GPx activities significantly decreased and MDA increased after HD. We also found that there was a significantly negative correlation between SOD and GPx with MDA. The results suggest that elevated level of plasma MDA and reduced activities of SOD and GPx can be caused oxidative stress, which may play a critical role in HD complications.