MRgFUS (MR guided Focused Ultrasound) being one of the non-surgical ablation techniques. We have already achieved favorable results in the past clinical study of MRgFUS to local treatment. New twenty one cases of invasive/noninvasive ductal carcinoma of the breast were treated by MRgFUS. Core needle biopsy led to the definitive diagnosis. All the patients were positioned prone in the treatment, using the therapeutic apparatus such as Signa Excite 1.5 T for MRI and ExAblate 2000 version 2.6/4.1 for FUS. Irradiation was not applied to all the 21 cases after MRgFUS. Axillary lymph node metastases were examined by dissection or sentinel lymph node biopsy. Recurrence or abnormal area of residual cancer was treated with Re-MRgFUS or ablated by usual surgery. All the 21 cases were from women patients. Median age is 54 years (range: 34-72). Median diameter of tumor is 15 mm (range: 5-50). As for the numbers of treatment, 17 patients were treated once, and 4 patients twice. Median period of observation is 14 months (range: 3-26). One case of recurrence of pure mucinous carcinoma was experienced. No evidences of recurrence were obtained through MRI for the rest of 20 cases. Skin burns were found in 2 cases. The patient had dimple on the skin immediately above tumor. In conclusion, MRgFUS is a good mean as local control of breast cancer, but the indicated case must be selected strictly. And it needs to observe longer the patients who ware treated by MRgFUS alone.