A 32-year-old woman who 1 year earlier underwent a right mastectomy for stage II breast cancer with the histology of invasive ductal carcinoma (scirrhus type) was admitted due to recurrent, metastatic breast cancer in January 1997. She presented multiple metastatic lesions in the skin, lymph nodes, bone, lungs, liver, and spleen, and her bone marrow was replaced almost entirely by tumor cells. The patient was sequentially treated with 5 courses of cyclophosphamide (CPA) and adriamycin (ADM) (CA); 2 courses of CPA, ADM, and 5-fluorouracil; 5 caurses of docetaxel hydrate; and 1 course of CA. After recovery of the normal bone marrow by standard-dose chemotherapies, peripheral blood stem cells (PBSC) were then collected after mobilization with G-CSF. The number of breast cancer cells in bone marrow and PBSC samples was determined by immunocytochemical staining with an anti-cytokeratin monoclonal antibody. The number of tumor cells in PBSC sample was within the level for non-metastatic breast cancer. Complete remission was obtained with high-dose chemotherapy consisting of CPA and Thio-TEPA, and supported by autologous PBSC transplantation.