Introduction: The main objective of this study was to investigate the effects of magnesium, zinc, vitamins C and E, and a combination of these micronutrients with vitamin B groups (B1, B2, B6, B12, folic acid and biotin) on blood pressure in type 2 diabetic patients. Materials and Methods: In a randomized, double-blind, placebo controlled clinical trial, 67 type 2 diabetic patients, 36-69 years old, stratified for sex and were randomly divided into three groups. Each subject received two capsules per day for a period of 4 months, each capsule containing one of the following preparations: Group 1 received 250 mg magnesium and 20 mg zinc, 200 mg vitamin C and 100 mg vitamin E, 10 mg vitamin B1, 10 mg vitamin B2, 10 mg vitamin B6, 10 μg vitamin B12 and 1 mg folic acid (n=22). Group 2: 250 mg magnesium and 20 mg zinc, 200 mg vitamin C and 100 mg vitamin E, (n=23), and group P: placebo (n=22). Blood pressure and biochemical analysis were determined at the beginning and after 2 and 4 months. Fasting blood glucose and HbA1c were determined by glucose oxidase and chromatography methods, respectively. Plasma vitamin C and serum magnesium and zinc were determined by the colorimetric method and serum α-tocopherol using HPLC. Serum malondialdehyde (MDA) was determined by a colorimetric method. Treatment effects were analyzed by general linear modelling. Results: Results indicate that after 2 and 4 months of supplementation levels of plasma vitamin C increased in group 1 (p<0.0001) and group 2 (p=0.029 and p<0.0001, respectively). Serum vitamin E increased in group 1 and 2 (p<0.0001) and serum folic acid increased in group 1, after 2 and 4 months supplementation (p<0.0001). Serum magnesium increased in group 1 after 2 months supplementation (p=0.001) but not after 4 months. After 2 or 4 months supplementation, there were no significant changes in fasting blood glucose or HbA1c in the 3 intervention groups. Levels of systolic blood pressure decreased significantly in group 2 after 4 months supplementation (p=0.012). After 2 and 4 months supplementation, diastolic blood pressure decreased significantly in group 1 (p=0.003 and p=0.012, respectively) and in group 2 (p<0.0001 and p=0.002, respectively) and mean arterial blood pressure decreased in group 1 (p=0.018 and p=0.025, respectively) and in group 2 (p=0.002). Also serum malondialdehyde decreased significantly in groups 1 and 2 (p=0.009 and p=0.041, respectively) after 4 months. Conclusion: The results of the present study indicate that in type 2 diabetic patients, combination of vitamins and minerals might decrease blood pressure.