The questionnaire used in this study provides increased information regarding the oral and dental function that is frequently affected by radiation therapy. Results of this study indicate the need to determine oral dysfunction after head and neck cancer therapy, so that the most predictable cure or best palliation of the malignancy with the least impact on oral function and quality of life is chosen. Oral complications during and after radiation therapy for head and neck cancer are common and affect quality of life. Oral QOL does not return to pretreatment levels by 6 months after radiation therapy. This study supports the use of a general function scale such as the EORTC questionnaire with the addition of disease/site-specific scales to provide data on outcomes of therapy and on the complications associated with therapy. The EORTC QLQ 30 questionnaire with the oral assessment addendum provides a measure of the quality of life and oral function in head and neck cancer patients and may provide useful outcome measures for assessment of oral care prevention and management strategies in these patient populations. The results show that the questionnaire is responsive to change throughout the course of radiation therapy for head and neck cancer.