Background: Sarcopenia might be a relevant lead for optimization of the condition of patients with head and neck cancer (HNC) before chemoradiotherapy (CRT) to prevent long-term functional swallowing impairment, such as feeding tube dependency. Methods: Regression analyses were performed to assess the association between skeletal muscle mass index (SMI), as a measure of sarcopenia, and prolonged (>90 days) feeding tube dependency in 128 patients with HNC treated with primary CRT. Results: Sixty-one patients (48%) became prolonged feeding tube-dependent. Lower SMI increased the risk of prolonged feeding tube dependency in multivariable analysis (risk ratio 1.08; 95% confidence interval 1.02-1.14, P =.01) adjusted for body mass index, abnormal diet, and socioeconomic status. Conclusions: Sarcopenia contributes to the risk of prolonged feeding tube dependency of patients with HNC treated with primary CRT. As sarcopenia might be a modifiable factor prior to treatment, it should be explored as a target for pretreatment patients' condition.