This single arm study will assess the efficacy and safety of Xeloda in combination with oxaliplatin as first-line chemotherapy in patients with advanced and/or metastatic gastric cancer who have had no prior chemotherapy for advanced or metastatic disease. Eligible patients will receive Xeloda 1000mg/m2 po twice daily, D1-D10 every 2 weeks (10 days treatment followed by 4 days rest period) plus oxaliplatin 85 mg/m2/day iv, D1 every 2 weeks. The anticipated time on study treatment is until disease progression, and the target sample size is <100 individuals.