PURPOSE: The purpose of our study was to investigate the feasibility of US-guided clip implantation in patients receiving neoadjuvant chemotherapy for treatment of breast cancer. MATERIALS AND METHODS: From January to May 2012, marker clips were inserted with US guidance in or adjacent to 23 tumors in 20 female patients receiving neoadjuvant chemotherapy for treatment of breast cancer at our institution. One radiologist performed a retrospective review of the identification of tumors on US, mammography,and breast MRI, and MRI artifact caused by a marker clip. Clip migration was evaluated using the clip-to-nipple distance on mammography obtained immediately after clip insertion and ithin one week before breast surgery. Complication associated with clip insertion was also observed. RESULTS: After completion of neoadjuvant chemotherapy, all tumors showed a decrease in size, and 13 of 23 (56.5%) tumors were no longer palpable and thus required preoperative localization. In addition, marker clips were the only remaining evidence of the original tumor site in three of 23 (13.0%) tumors at the time of preoperative localization. All signal voids caused by a marker clip on breast MRI were less than 1 cm, which did not have a significant effect on detection and evaluation of the extent of the breast cancer. The mean change of the clip-to-nipple distance was 2.11 mm on a craniocaudal, and 2.67 mm on a mediolateral mammogram. No complication associated with clip insertion was observed in any case. CONCLUSION: US-guided clip implantation in or adjacent to a breast cancer is safe and feasible for patients with anticipation of complete or near complete response to neoadjuvant chemotherapy.