Background: Patients with metastatic esophageal squamous cell cancer (ESCC) need safer and more efficacious treatments. The aim of this phase II study was to investigate the efficacy and safety of S-1 plus cisplatin as first-line therapy in metastatic ESCC. Patients and Methods: 50 patients with metastatic ESCC who had not received prior systemic chemotherapy for metastatic disease were enrolled. Patients received S-1 at 40 mg/m2 divided into 2 daily doses for 14 days and cisplatin at 75 mg/m2 on day 1 or 25 mg/m2 on days 1-3 intravenously, repeated every 21 days with a maximum of 6 cycles. Results: 47 patients were assessable for response and 18 patients achieved a partial response, giving an overall response rate of 38.3%. Among those who had objective responses, a large percentage (72.2%) quickly showed remarkable tumor shrinkage during the first 2 cycles. 18 (38.3%) patients had stable disease. The median progression-free survival was 5.6 months, and the median overall survival was 12.0 months. Toxicity was mild to moderate and generally tolerable. Conclusion: The combination of S-1 plus cisplatin was a well-tolerated and convenient chemotherapy regimen with promising efficacy.