Objective: To investigate the relationship between the expression of p73α and p53 versus the chemosensitivity in breast cancer cells. Methods: Twelve surgical samples of breast cancer diagnosed by pathology were used. The cancer sample cells were separately cultured in the incubator at 37°C, 5% CO2 in vitro. The relative inhibition rate of cancer cells by 4 kinds of anticancer drugs, which were EPI, MMC, 5-Fu and DDP, were assayed by MTT method. Immunocytochemistry was used to detect the expression of p73α and p53 in the cancer cells. Results: The positive expression of p73α was found in 5/12 (41.67%), and p53 positive expression rate was 50.0% (6/12). The relative inhibition rate of MMC, EPI, 5-Fu and DDP were significantly higher in the p73α positive cancer cells than in the p73α negative cancer cells. A positive correlation was found between expression of p73α and chemosensitivity for all the four anticancer drugs. Conclusion: The expression of p73α is related with the chemosensitivity of the breast cancer cells, and it may become one of the markers for judging the effect of chemotherapy in clinic.