The nature of swallowing problems was examined in nine patients treated primarily with external-beam radiation and adjuvant chemotherapy for newly diagnosed tumors of the head and neck. All subjects underwent videofluorographic examination of their swallowing. Three analyses were completed, including the following: observations of motility disorders, residue, and aspiration; temporal analyses; and biomechanical analyses. Oropharyngeal swallow efficiency was calculated for the first swallow of each bolus. Swallow motility disorders were observed in both the oral and pharyngeal stages. Seven of the nine patients demonstrated reduced posterior tongue base movement toward the posterior pharyngeal wall and reduced laryngeal elevation during the swallow. Oropharyngeal swallow efficiency measures were significantly lower in the nine irradiated patients than in age-matched normal subjects. Between patients and normal subjects, significant differences were found in the measures of timing and distance of pharyngeal structural movements during the swallow, as well as in the measures of coordination during the swallow. Although treatment of head and neck cancer with external-beam radiation is designed to provide cancer cure and preserve organ functioning, oral and pharyngeal motility for swallow can become compromised if external-beam radiation treatment is provided to either the larynx or tongue base regions.