A 51-year-old postmenopausal woman was diagnosed as having adenocarcinoma (gastric cancer type 4) from gastric biopsy by upper endoscopy. Her chief complaint was abdominal dilatation. Meanwhile, a breast CT suggested tumor in her left breast and was diagnosed as an invasive lobular carcinoma based on a core needle biopsy. After gastric biopsy, tissues are stained by ER and PgR in immunohistochemistry. The diagnosis was modified from gastric cancer to T2N1M1, stage IV left breast cancer, accompanied by a treatment. Chemotherapy with EC 6 course consisted of a weekly PTX 4 course (epirubicin, cyclophosphamide-weekly paclitaxel) was performed. After the chemotherapy, breast mass, ascites and tumor marker were dramatically improved. Then hormonal therapy was administered. She passed away 2 and 1/2 years after her first visit to the hospital. Metastatic gastric tumors simulating type 4 advanced gastric cancer (MGTS type 4) and invasive lobular carcinoma are known to have an unfavorable prognosis. There is no doubt, however, that the multidisciplinary treatments have brought a satisfaction to her and family. We should keep in mind a possibility of gastric metastasis of breast cancer, when consulting a female patient with gastric cancer type 4.