A phase I study of combination neoadjuvant chemotherapy with docetaxel (DOC) and nadaplatin (CDGP) was conducted in patients with untreated, advanced but operable oral squamous cell carcinoma. DOC was administered (one-hour i.v. infusion) on day 1 followed by CDGP (one-hour i.v. infusion). The dose levels of DOC and CDGP tested were 60/70, 60/80, 60/90, 60/100, and 70/100 (mg/m(2)). Fifteen patients enrolled in this study and median age was 60 years. Dose-limiting toxicity (DLT) occurred in one of six patients at DOC dose of 60 mg/m(2) and CDGP dose of 100 mg/m(2). The DLT was diarrhea. Because one additional patient at this dose-level developed grade 4 neutropenia lasting for 4 days that approached DLT and because fear of severe hematological problems was predicted, further dose escalation was not performed. This combination chemotherapy is active and well tolerated and warrants a phase II study. We recommended 60 mg/m(2) DOC and 100 mg/m(2) CDGP for phase II study.