Mitoxantrone (MIT) is a new anthraquinone anti-cancer agent. We successfully treated 3 patients with locally advanced breast cancer, including two inflammatory breast cancers, by pre-operative arterial injection of MIT. The treatment protocol was MIT 12 mg/m2 injected into both the internal mammary and the subclavian artery with oral administration of 5' DFUR 1,200 mg/day. In two cases of inflammatory breast cancer, the redness of skin was immediately reduced after the first course. After 2 courses, all tumors were decreased over 50% in size. Standard radical mastectomy could be carried out on all patients. Preoperative arterial injection of MIT might be the treatment of choice for locally advanced breast cancer. This preliminary result encourages further study.