A 43-year-old woman who complained of abdominal fullness, appetite loss, and constipation was diagnosed as unresectable advanced schirrhous gastric cancer with left supra-clavicular lymph node metastases, massive ascites, rectal stenosis, and bilateral hydronephrosis due to peritoneal metastases. The biopsy specimen showed a poorly differentiated adenocarcinoma with signet-ring cells. After placement of the bilateral ureteral stents, she was treated with combined chemotherapy of biweekly paclitaxel (120 mg/m2, day 1, day 15) and TS-1 (80 mg/day, days 1-14 with 2-weeks rest). Subjective symptoms were relieved after one course of the chemotherapy. After 3 courses, computed tomography showed markedly reduced supra-clavicular lymph node metastases and no ascites. Radiographic and endoscopic examinations also demonstrated remarkable improvements in compliance of the gastric and rectal walls. These findings suggested that partial response on Response Evaluation Criteria in Solid Tumors (RECIST) was obtained. After the first course, the treatment was continued on an outpatient basis. There were no adverse effects over grade 2 throughout six courses of the chemotherapy. The biweekly paclitaxel and TS-1 chemotherapy may well be an effective treatment for advanced schirrhous gastric cancer with carcinomatous peritonitis.