A man is his 50s experienced epigastric discomfort and body weight loss from 60 to 56 kg over 3 months. A lesion was diagnosed as type 3 advanced gastric cancer (group 5, tub2) with para-aortic lymph node and multiple liver metastases. Pretreatment hemoglobin(Hb), albumin(Alb), and C-reactive protein(CRP) levels were 11.0 mg/dL, 3.0 g/dL, and 2.40 mg/dL, respectively. S-1+cisplatin (CDDP) combined chemotherapy (S-1 120 mg/day, day 1-21, CDDP 60 mg/ m2, day 8, q35 days) with nutritional supportive care using enteral nutrition (EN) agent (Prosure) enriched with eicosapentaenoic acid (EPA) was initiated. After 6 weeks, body weight, Hb, Alb, and CRP improved to 60 kg, 13.6 mg/dL, 4.6 g /dL, and 0.14 mg/dL, respectively. Moreover, a marked reduction in para-aortic lymph node and multiple liver metastases was seen on computed tomography (CT) scans 12 weeks after treatment initiation. Accordingly, nutritional supportive care using EN agent enriched with EPA during chemotherapy might be an effective treatment for patients with gastric cancer who show increased CRP and decreased albumin levels.