Diabetic patients need nutritional education more than those suffering from other diseases because of the necessity of controlling blood glucose levels with dietary treatment. The purpose of this study was to find out the effectiveness of nutrition education on diabetes control and antioxidant status, both of which are related to diabetic complications. Thirty (15 males and 15 females) type 2 diabetes mellitus patients aged $66.7{\pm}8.8$ years participated in a 4-week nutrition education program. Nutrient intakes, blood glucose level, antioxidant status, and DNA damage were evaluated before, immediately after, and three months after the education program. Changes in those parameters over time were analyzed using repeated-measures analysis of covariance. Over time, HbA1c (p=0.000), plasma total cholesterol (p=0.002), plasma thiobarbituric acid related substances (TBARS; p=0.000), and leukocyte DNA damage (p=0.000) significantly decreased; plasma retinol (p=0.001), plasma tocopherol (p=0.000), erythrocyte catalase (CAT; p=0.000), and erythrocyte glutathione peroxidase (GPx; p=0.000) significantly increased. In an evaluation of nutrient intakes by Dietary Reference Intakes for Koreans (KDRI), energy (p=0.009), phosphorus (p=0.033), sodium (p=0.001), potassium (p=0.019), zinc (p=0.043), riboflavin (p=0.050), folic acid (p=0.048) and vitamin C (p=0.008) intakes had significant positive changes. In a correlation analysis of the biochemical and nutritional changes resulting from the education program, plasma TBARS were negatively correlated with potassium (r=-0.418, p<0.05), iron (r=-0.443, p<0.05), riboflavin (r=-0.432, p<0.05), and folic acid (r=-0.446, p<0.05) intakes, while plasma retinol was positively correlated with energy (r=0.543, p<0.01), protein (r=0.543, p<0.01), phosphorus (r=0.425, p<0.05), iron (r=0.485, p<0.05), zinc (r=0.570, p<0.01) and niacin (r=0.510, p<0.05) intakes. Erythrocyte CAT was positively correlated with folic acid intake (r=0.605, p<0.01). From these results, we suggest that an improvement in nutrition resulting from a diabetic education program for type 2 diabetes patients led to improvement in their antioxidant status, also possibly reducing complications resulting from diabetes.