A 69-year-old woman had a 7 x 6 cm tumor on her left breast with ipsilateral axillary lymph node swelling and multiple liver metastases as detected on CT scan (T 3 N 2 M 1 b, Stage IV). Core needle biopsy and immunohistochemistry of breast tumor showed invasive ductal carcinoma with negative hormone receptor and overexpression of HER 2. After a treatment failure of 3 months weekly trastuzumab monotherapy, a combination of bi-weekly trastuzumab and paclitaxel (weekly 6, bi-weekly 9 courses), was given. Tumor markers became negative 4 months later, and multiple liver nodules, breast tumor and axillary nodes completely disappeared 9 months later. Breast surgery was avoided, and CR was maintained more than 8 months only with bi-weekly trastuzumab. From the standpoint of the patient's convenience,a bi-weekly schedule of trastuzumab and paclitaxel could be a promising treatment choice for metastatic breast cancer.