Dysphagia is commonly seen in patients undergoing radiation-based therapy for locally advanced squamous carcinoma of the head and neck. Within 4 to 5 weeks of starting therapy, patients develop mucositis, radiation dermatitis, and edema of the soft tissues. Resulting pain, copious mucous production, xerostomia, and tissue swelling contribute to acute dysphagia. As the acute effects resolve, late effects including fibrosis, lymphedema, and damage to neural structures become manifest. Both acute and late effects result in adverse sequelae including aspiration, feeding tube dependence, and nutritional deficiencies. Early referral for evaluation by speech-language pathologists is critical to (1) ensure adequate assessment of swallow function, (2) determine whether further testing is needed to diagnose or treat the swallowing disorder, (3) generate a treatment plan that includes patient education and swallow therapy, (4) work with dieticians to ensure adequate and safe nutrition, and (5) identify patients with clinically significant aspiration. © 2009 Elsevier Inc. All rights reserved.