PURPOSE The purpose of this study was to evaluate the effect of antioxidant vitamins and magnesium supplementation on fasting blood glucose and lipids in patients with type 2 diabetes. METHODS This study is a unequivalent control group pretest-posttest design. Seventy-one subjects with type 2 diabetes who were recruited from home visiting clients of a public health center, completed the trial. The experimental group entered a 12-week treatment period with antioxidant vitamins and magnesium and the control group with no antioxidant vitamins and magnesium. RESULTS Serum level of fasting blood glucose decreased from 134.7 mg/dl to 125.0 mg/dl and total-cholesterol decreased from 215.5 mg/dl to 198.2 mg/dl in the experimental group. No changes in fasting blood glucose and total-cholesterol were demonstrated in the control group. CONCLUSIONS A short-term supplementation with antioxidant vitamins and magnesium can reduce fasting blood glucose and total-cholesterol in patients with type 2 diabetes. The continuous effect of this supplementation and the beneficial effect on the prevention of diabetes complication still needs to be demonstrated.