Ten patients with breast cancer and a breast cancer susceptibility gene 1 (BRCA1) mutation, who presented with stages I to III breast cancer between December 2006 and 2007, were treated with four cycles of neoadjuvant cisplatin, followed by mastectomy and conventional chemotherapy. The excised breast tissue and lymph nodes were examined for the presence of residual disease. Pathologic complete response was observed in nine patients (90%). Platinum-based chemotherapy appears to be effective in a high proportion of patients with BRCA1-associated breast cancers. Clinical trials are now warranted to determine the optimum treatment for this subgroup of breast cancer patients.