INTRODUCTION: This phase II trial evaluated the efficacy and safety of cetuximab combined with FOLFOX6 (leucovorin [LV] 5-fluorouracil [5-FU]/oxaliplatin) in the first-line treatment of patients with advanced or metastatic colorectal cancer. PATIENTS AND METHODS: Patients with locally advanced or metastatic CRC who had received no previous therapy for advanced disease were treated with cetuximab at a loading dose of 400 mg/m2 followed by 250 mg/m2 weekly and a FOLFOX6 regimen every 2 weeks consisting of oxaliplatin 85 mg/m2, LV 400 mg/m2, and 5-FU bolus 400 mg/m2 followed by 5-FU continuous infusion 2400 mg/m2 over 46 hours. RESULTS: A total of 82 eligible patients were enrolled; epidermal growth factor receptor expression was positive in 67 patients. The overall response rate was 44.8%. In addition, 30 patients (44.8%) in the evaluable population experienced stable disease. Median time to progression or death was 9.3 months (95% CI, 7.0-11.3 months), and median survival was 21.7 months (95% CI, 17.5-27.8 months). Patients who experienced skin toxicity had a statistically significant and longer median survival time than those patients with no skin toxicity (P = .0001). The most commonly observed toxicities were neutropenia (65%), fatigue (56.3%), diarrhea (53.8%), nausea (50%), acneiform rash (41.3%), and stomatitis (35%). CONCLUSION: Our results demonstrate that cetuximab can be safely combined with FOLFOX6 for the first-line treatment of patients with metastatic CRC (mCRC). The efficacy parameters are similar to other first-line regimens in mCRC. Because of the emergence of KRAS as a predictive marker, this regimen has promise in KRAS wild-type mCRC.