Background: The benefit of chemoradiation (CTRT) in the treatment of locally advanced head and neck cancer (LAHNC) declines in older and sicker patients. In 2006, the FDA approved cetuximab in LAHNC. Cetuximab with radiation has a perceived lower side effect profile compared to standard chemotherapies used in CTRT. Our objective was to examine the impact of cetuximab on the use of CTRT in elderly patients with LAHNC. Methods: We identified adults aged 66 and older diagnosed with LAHNC between 1999 and 2007 in the Surveillance Epidemiology and End Results (SEER)-Medicare linked database. Treatment was categorized as CTRT or other based on Medicare claims within 6 months of diagnosis. We excluded patients who did not receive definitive treatment. In patients who had CTRT, we identified use of cetuximab based on drug-specific billing codes. We assessed trends in the use of CTRT over the entire study period and in the use of cetuximab since 2006. We examined the influence of age and comorbidity on the likelihood of receiving CTRT before and after 2006 adjusting for clinical and demographic factors. Results: We identified 4,809 patients with LAHNC. One-fourth were ≥80 years and almost a fifth had a Charlson comorbidity score (CCS) of ≥2. Overall more than 20% of patients received CTRT. The use of CTRT more than tripled over time, from 10% of patients diagnosed in 1999 to 38% in 2007 (p<0.0001 for trend). Of the 336 patients who had CTRT since 2006, 45% received cetuximab. Prior to 2006, patients ≥80 years or those with a CCS of ≥2 were significantly less likely to be treated with CTRT compared to younger patients or those with a CCS of 0. In patients diagnosed in 2006 or later, age and comorbidity no longer predicted the likelihood of receiving CTRT. Conclusions: In this population-based cohort of older adults, the use of CTRT increased substantially over time. The availability of cetuximab, with a perceived gentler side effect profile, may have increased the use of CTRT, especially in older and sicker patients.