Oxidative stress resulting from an imbalance between pro-oxidants and anti-oxidants seems to play an important role in human breast carcinogenesis. There are conflicting reports regarding the tissue levels of malondialdehyde (MDA), ascorbic acid and superoxide dismutase (SOD) in breast cancer patients whereas few blood values have been reported. The present study was carried out to observe the changes in serum MDA, serum SOD and plasma ascorbic acid with the stage-wise progression of the disease. Serum MDA and serum SOD levels were found to be increased gradually from Stage I to Stage IV as compared to control group (p < 0.001). The maximum rise was in Stage IV patients. In contrast, mean plasma ascorbic acid levels were low in all stages compared to control group (p < 0.001). The decrease was more pronounced in Stage III and Stage IV. The study would be of immense help for establishing blood based biochemical marker in breast cancer patients.