Objective To investigate ERCC1 expression in advanced breast cancer and its relationship with cisplatin resistance. Methods ERCC1 expression in 50 cases of advanced breast cancer was measured by RT-QPCR. The chemotherapy (CAF) was given. Gemcitabine and cisplatin were given because of metastasis. Results The expression of ERCC1 has no relationship with age, lymph node metastasis, clinicl stage, histologi-cal grade or human epidermal growth factor receptor-2 (HER2) expression. The effective rate was 18.8% (3/16) for ERCC1 high-expressed patients and 79.4%(27/34)for ERCC1 low-expressed patients in terms of cisplatin chemotherapy. The sensitity for cisplatin chemotherapy was high for patients with low ERCC1 expression and it was low for patients with high ERCC1 expression. The effective rate (complete remission+partial remission), and ineffective rate (stable disease+progressive disease) between the two had statastical significance (P<0.001). Con-clusions ERCC1 low-expressed patients can benefit from cisplatin. ERCC1 can be used as a moleculer marker for predicting chemotherapy efficacy in breast cancer.