We tested the in vitro sensitivity of 170 primary breast carcinoma samples to the anti-cancer drugs conventionally used in clinical chemotherapy. It was found that: 1. The high sensitivity rate (HSR) of breast carcinoma cells to 5-fluorouracil (5-Fu), mitomycin (MMC), cisplatin (DDP), adriamycin(ADM), methotrexate(MTX), vincristin(VCR), vepesid(VP-16), taxol, and vindesine(VDS) were 57.1%, 49.4%, 48.3%, 35.8%, 21.8%, 21.2%, 10%, 18.2% and 20.9%, respectively. The increase of HSR of cancer cells to 5-Fu, MMC, DDP, taxol was more significant than that of the other drugs tested (P < 0.05). 2. No correlation was shown between drug sensitivity and factors, i.e. pathological type, clinical type, expression of estrogen receptor (ER) and epithelium growth factor receptor(EGFR) for breast carcinoma (P > 0.05). 3. Cyclosporin A can increase part of the sensitivity of ADM-resistant breast carcinoma cells to ADM.