Swallowing is a rapid, dynamic and complex process. Surgical treatment of head and neck malignancies produces significant alterations in the swallowing mechanism. The modified barium swallow allows assessment of these physiologic and anatomic derangements in the postoperative patient. Small amounts of liquid barium, barium paste and a cookie coated with barium are ingested by the patient and the swallowing mechanism is recorded by videofluoroscopy. Unlike the routine barium swallow in which only the esophageal stage of swallowing is studied, using the modified barium swallow all four stages of swallowing are studied with particular emphasis on the oral and pharyngeal stages. Our experience with the modified barium swallow has shown it to be a valuable adjunct in the rehabilitation of the post-surgical patient allowing the otolaryngologist and speech pathologist to identify and modify swallowing abnormalities. Presentation of specific swallowing mechanism deficits as demonstrated using the modified barium swallow will be shown and appropriate therapeutic interventions discussed.