A 46-year-old woman who had received mastectomy for breast cancer 6 years earlier complained of abdominal distension. Computed tomography and ultrasonography revealed massive ascites and ovarian swelling of both sides. She was diagnosed as having primary ovarian cancer and peritoneal dissemination, and underwent a total hysterectomy as well as ovarectomy on both sides. After surgery, she received a sequential chemotherapy, ie, intraabdominal injection of carboplatin (CBDCA 300 mg/m2) and div administration of paclitaxel (PTX 180 mg/m2) as a standard regimen for advanced ovarian cancer. However, detailed histological examinations showed that the ovarian cancer had metastasized from her breast cancer. It is well-known that breast cancer easily metastasizes to the bone, liver, pleura and lymph node, but rarely to the ovarium or peritoneum when chemotherapy is conducted. Therefore, no standard therapy has been established for breast cancer metastasizing to the ovarium. Our patient received 4 cycles of weekly administration of PTX (PTX 80 mg/m2, 3 consecutive weeks, 1-week break), followed by oral administration of doxifluridine+anastrozole on an outpatient basis. No evidence of recurrence of breast cancer has been noted 1 year after surgery. This result suggests that weekly administration of PTX and intraabdominal injection of CBDCA might be beneficial in the treatment of recurrent breast cancer associated with metastatic ovarian cancer and peritoneal dissemination after operation.