The patient was a 66-year-old man. Total abdominal gastrectomy and D2 dissection were performed for gastric cancer (cT3N0M0P0CYXH0, cStage II A). Pathological examination confirmed a diagnosis of Stage III C mucinous adenocarcinoma (pT4pN3pM0, pStage III C). He underwent adjuvant chemotherapy with TS-1(120mg/body). One year after adjuvant chemotherapy, anastomotic stricture was caused. Although it was not possible to point out recurrent lesions on the CT image, we strongly suspected that extrinsic compression around the anastomotic portion was due to peritoneal dissemination recurrence because of symptoms and marked tumor elevation. Therefore, TS-1(120mg/body)plus cisplatin(CDDP 60mg/m2)were administered as first-line therapy for advanced gastric cancer. TS-1 plus CDDP(SP)chemotherapy resulted in marked tumor reduction and improved symptoms. However, after 33 courses of SP chemotherapy, renal function was worse due to cisplatin; thus, docetaxel(DTX 70mg/m2)was administered as second line therapy. After 8 courses of DTX, peritoneal dissemination recurrence was diagnosed, and the patient was treated with irinotecan(CPT-11 150mg/m / 2), ramucirumab(RAM 8 mg/kg) plus paclitaxel(PTX 80mg/m2 day 1, 8, 15). However, the disease worsened. The side effect of SP therapy was renal dysfunction. Nonetheless, we experienced that long-term disease control could be achieved by administering chemotherapy under strict follow-up.