Serum copper, zinc levels, and the Cu/Zn ratio were evaluated in 31 patients with breast cancer and 35 healthy controls. Copper and zinc were determined by atomic absorbtion spectrophotometry. The mean serum copper level and the mean Cu/Zn ratio in patients with breast cancer were significantly higher than the control group (p < 0.001 and p < 0.001). In addition, the mean serum zinc level in patients with breast cancer was significantly lower than the control group (p < 0.001). Neither serum copper and zinc levels nor the Cu/Zn ratio were of value in discriminating of the disease activity and severity. Interestingly, the Cu/Zn ratio in premenopausal patients was higher than postmenopausal patients (p < 0.05) and this was not related to age. The further combined biological and epidemiological studies are necessary to investigate the roles of copper and zinc in breast cancer.