 This study will compare capecitabineoxaliplatin as adjuvant chemotherapy versus observation alone in chemotherapy-naive participants who have undergone potentially curative resection for gastric cancer. Participants will be randomized to either the chemotherapy arm or the observation arm. Capecitabine will be administered orally, 1000 milligrams per meter-squared mgm2 twice daily BID on Days 1 to 15 of a 3-week cycle, for 8 cycles, and oxaliplatin will be administered as an intravenous IV infusion, 130 mgm2 every 3 weeks for 8 cycles. The anticipated time on study treatment in 6 months and the target sample size is 1024 individuals. 