We report a case of local advanced breast cancer with multiple lung metastases (T4bN2M1) achieving a significant improvement of QOL by multimodal therapy with chemotherapy, antibody therapy, radiation therapy and surgery. The patient was a 47-year-old woman with mental deterioration who had an ulcerative breast cancer with multiple lung metastases. Breast biopsy led to a diagnosis of an invasive ductal carcinoma positive for erbB2 protein expression. She received 6 cycles of tri-weekly docetaxel (60 mg/m2) and weekly trastuzumab. Although metastases in the lung disappeared after chemotherapy, the response of breast ulceration was less satisfactory. Simple mastectomy followed by radiation therapy (50 Gy) to the axilla was performed as a palliative treatment. No signs of recurrence were observed for more than 14 months of treatment by trastuzumab. Multimodal therapy can improve patient QOL and the clinical outcomes in Stage IV local advanced breast cancer.