Twenty patients with hypernasal speech were studied with both flexible fiber optic nasopharyngoscopy and multi-view videofluoroscopy, as well as behavioral speech assessment. Characteristic diagnostic findings showed the hypernasality to be caused by hypertrophic tonsils with posterior placement of the upper poles of the tonsils into the oropharyngeal and nasopharyngeal airway. In 16 of the 20 cases, there was a complete resolution of hypernasal speech following only tonsillectomy with no other treatments. Three patients required a brief period of speech therapy and one additional patient required both speech therapy and temporary prosthetic treatment (speech bulb reduction).