Purpose: To report results of a randomized phase II trial (Radiation Therapy Oncology Group RTOG-0234) examining concurrent chemoradiotherapy and cetuximab in the postoperative treatment of patients with squamous cell carcinoma of the head and neck (SCCHN) with high-risk pathologic features. Patients and Methods: Eligibility required pathologic stage III to IV SCCHN with gross total resection showing positive margins and/or extracapsular nodal extension and/or two or more nodal metastases. Patients were randomly assigned to 60 Gy radiation with cetuximab once per week plus either cisplatin 30 mg/m2 or docetaxel 15 mg/m2 once per week. Results: Between April 2004 and December 2006, 238 patients were enrolled. With a median follow-up of 4.4 years, 2-year overall survival (OS) was 69% for the cisplatin arm and 79% for the docetaxel arm; 2-year disease-free survival (DFS) was 57% and 66%, respectively. Patients with p16-positive oropharynx tumors showed markedly improved survival outcome relative to patients with p16-negative oropharynx tumors. Grade 3 to 4 myelosuppression was observed in 28% of patients in the cisplatin arm and 14% in the docetaxel arm; mucositis was observed in 56% and 54%, respectively. DFS in this study was compared with that in the chemoradiotherapy arm of the RTOG-9501 trial (Phase III Intergroup Trial of Surgery Followed by Radiotherapy Versus Radiochemotherapy for Resectable High Risk Squamous Cell Carcinoma of the Head and Neck), which had a hazard ratio of 0.76 for the cisplatin arm versus control (P = .05) and 0.69 for the docetaxel arm versus control (P = .01), reflecting absolute improvement in 2-year DFS of 2.5% and 11.1%, respectively. Conclusion: The delivery of postoperative chemoradiotherapy and cetuximab to patients with SCCHN is feasible and tolerated with predictable toxicity. The docetaxel regimen shows favorable outcome with improved DFS and OS relative to historical controls and has commenced formal testing in a phase II/III trial.