Background: Recently the carcinogenic and toxic effects of some heavy metals such as chromium (Cr), and lead (Pb) through the mechanism of oxidative stress have been reported. Due to the various consequences of chemotherapeutic treatments on body hemostasis, the present study aimed to evaluate the effect of Adriamycin 60 mg/m2 and Cytoxan 600 mg/m2 (AC) chemotherapy on the serum levels of Cr, Pb, and the percent α-diphenyl-β-picrylhydrazyl (DPPH) inhibition. Methods: This study was performed on 50 patients with breast cancer at two separate sampling times, the first at the initiation of chemotherapy and the last at the end of three courses of the AC chemotherapy treatment. Serum levels of Cr and Pb were measured using atomic absorption spectrophotometry. The percent DPPH inhibition ( I) and also the effect of age and stage of the disease on the mentioned variables were evaluated. Statistical comparison of the obtained results before and after chemotherapy was performed using paired sample t-test. Intra-group evaluation of age and disease stages was done using an independent sample t-test. Results: A significant decrease was observed in the percent DPPH inhibition after 3 courses of chemotherapy (p<0.001). Cr and also Pb were significantly higher in patients with breast cancer after AC chemotherapy (p<0.001). Conclusion: According to the results, AC chemotherapy in patients with breast cancer is associated with higher levels of Cr and Pb, which can eventually lead to worsened oxidative stress status in affected patients. However, it seems that these changes do not necessarily depend on age and the stage of the disease.