The aim of this study was to investigate the effect of protein whey isolate supplementation on antioxidant status during a resistance training program in overweight young men. 30 individuals (body mass index between 25-30 kg.m2) participated in this study and were randomly divided into three groups (each 10 subjects): experimental group 1 (supplement + six weeks of resistance training) (W), experimental group 2 (placebo + six weeks of resistance training) (P), Control (C). Total antioxidant capacity (TAC) in the whey supplement group significantly increased in posttest compared with pretest (p<0.05). Glutathione (GSH) and vitamin C levels showed a significant increase in both whey supplement and placebo groups in posttest (p<0.05). It can be concluded that although exercise alone could improve the antioxidant system in the overweight subjects, the combination of resistance training and whey protein consumption had more effects.