The purpose of this study was to evaluate the effectiveness and adverse events of combination chemotherapy with oral S-1 administration following docetaxel (DOC) treatment by superselective intra-arterial infusion as neo-adjuvant chemotherapy (NAC) for patients with oral squamous cell carcinoma. Thirteen patients were enrolled in this study (9 men and 4 women, with a mean age of 61. 0 years). All patients were given S-1 65mg/m(2) per day for 14 days, and DOC 40-50mg/m(2) by intraarterial infusion was administered. The locoregional response evaluated 3 weeks after administration was 100%, including a 69. 2% complete response. According to Oboshi and Shimosato's classification, histological evaluation of surgical specimens revealed that 3 cases were Grade II a, 4 cases Grade II b, 1 case Grade IV a, and 4 cases Grade IV c. The severe side effects were neutropenia and cerebral infarction. The present study suggests that combination chemotherapy with S-1 and DOC by superselective intra-arterial infusion would be an effective and safe regimen in NAC for oral squamous cell carcinomas.