Abstract Background and Objective: The purpose of this study was to determine the effect of dietary supplementation with zinc, magnesium and zinc plus magnesium on muscle strength in active women. Materials and Methods: Forty active women selected randomly were randomly divided into 4 groups of 10 each, all undergonig resistance training and receiving, daily, a supplement of either zinc (50 mg zinc sulfate), magnesium (250 mg magnesium oxide), or zinc plus magnesium (50 mg zinc sulfate plus 250 mg magnesium oxide), or no supplement (control group). All the subjects had a history of sports activity. Blood samples were collected and 1-RM was measured at the beginning and after 8weeks. Results: Independent and paired-sample t-test showed that zinc, magnesium and zinc plus magnesium supplements had no statistically significant effects on the strength of lower body muscles. However, the magnesium supplement had a significant positive effect on the strength of upper body muscles (chest, back, as well as back and hand bending muscles). In addition, the zinc and zinc plus magnesium supplements affected significantly the strength of the back and hand bending muscles. Further analysis of the data showed that the zinc plus magnesium supplement had no significant effect on the serum zinc and magnesium concentrations. Conclusion: Dietary supplementation with zinc, magnesium and zinc plus magnesium can effect desirably the upper body muscles strength in active women.