Here we report the case of a patient with advanced gastric cancer with esophageal invasion who was treated with chemotherapy using S-1 and cisplatin (CDDP) preoperatively. The patient was a 72-year-old woman who was diagnosed with advanced gastric cancer (T3N2M0) with esophageal invasion. S-1 was orally administered at 80 mg/day (60 mg/m(2) per day) on days 1-14 and CDDP was infused at 80 mg/day (60 mg/m(2) per day) on day 8, followed by a 1-week rest. Marked reductions in the sizes of the primary tumor and metastatic lymph nodes around the stomach were observed after two cycles of the therapy. Adverse reactions occurring during the therapy were only grade 2 gastrointestinal disorder and grade 1 leukocytopenia. Radiological and endoscopic examinations before surgery showed that a partial response (PR) had been achieved. The patient underwent curative surgery consisting of total gastrectomy, D2 lymph node dissection, and splenectomy. Her postoperative course was uneventful, without surgical complications. No gastric cancer cells were detected in the primary lesion or lymph nodes by immunohistochemical staining with cytokeratin, confirming a histological complete response (CR). As Epstein-Barr virus-encoded small RNA (EBER) had been detected by in-situ hybridization in the gastric cancer cells of a biopsy specimen, this tumor was diagnosed as an Epstein-Barr virus (EBV)-associated gastric carcinoma (EBVaGC), which was effectively treated with S-1 and cisplatin chemotherapy.