Our objective was to evaluate the efficacy and safety of capecitabine in chemotherapy-naive patients with unresectable advanced or metastatic gastric cancer. An open-label multicenter phase II study was conducted for previously untreated patients with advanced or metastatic gastric cancer. Oral capecitabine 828 mg/m2 twice daily was given on days 1-21 every 4 weeks. Baseline characteristics of 60 enrolled patients were: male/female 49/11, median age 64 years (range 28-74), good performance status (ECOG 0-1) in 98% of patients and 27 patients had prior gastrectomy (45%). A median of 4 treatment cycles were administered (range 1-37). Five patients were excluded from the efficacy analysis because they did not meet eligibility criteria. The overall response rate (RR) in the evaluable patient population (n=55) was 26% [95% confidence interval (95% CI) 15-39%] and a further 29% of patients had stable disease. The overall RR in the intent-to-treat population (n=60) was 23% (95% CI 13-36.0%). Median time to progression in the evaluable patient population was 3.4 months (95% CI 1.8-6.1) and overall survival time in the intent-to-treat population was 10.0 months (95% CI 6.4-13.6). The most frequent grade 3/4 drug-related adverse event was hand-foot syndrome (13%), but this was readily managed by treatment interruption and dose reduction. No patients developed grade 3/4 drug-related diarrhea, vomiting, leukopenia or thrombocytopenia. We conclude that this 4-week regimen of capecitabine showed promising activity and was well tolerated as first-line therapy for advanced/metastatic gastric cancer. Further investigation of this regimen is warranted.