BACKGROUND Advanced gastric cancer refers to tumor invasion into the gastric muscularis propria or even the layer beyond, and has low early gastric cancer diagnosis rate. OBJECTIVE To determine the clinical efficacy and side effects of neoadjuvant chemotherapy with tegafur, gimeracil, and oteracil potassium capsules (TGOP) combined with oxaliplatin (SOX regimen) in patients with advanced gastric cancer. METHODS We evaluated 25 patients with advanced gastric cancer who were admitted and treated with neoadjuvant chemotherapy with the SOX regimen (intravenous injection of 130 mg/m(2) oxaliplatin on day 1 followed by oral administration of 60 mg TGOP twice daily on days 1-14), every 3 weeks. The clinical efficacy and side effects of the SOX regimen were evaluated after two courses of treatment, before surgery. RESULTS Of the 25 patients enrolled in this study, 23 completed two courses of neoadjuvant chemotherapy, and of these, 12 achieved downstaging as determined by the clinical TNM stage, resulting in a total response rate of 52.2%. The 23 patients underwent surgery, with 22 receiving radical resection (95.7%). Among these 23 patients, R0 resection was achieved in 16 (69.6%) and pathological complete remission was observed in one. CONCLUSIONS Neoadjuvant chemotherapy with TGOP combined with oxaliplatin was effective for advanced gastric cancer and had tolerable side effects.