To examine the influence of smoking on observer based morbidity scores and patient assessed health related quality of life after treatment for head and neck cancer. The results of EORTC C30 and H&N35 questionnaires and DAHANCA morbidity scores were studied according to smoking status in 114 recurrence free head and neck cancer patients. In contrast to observer based toxicity scoring, smoking had a significantly negative influence on 20 of the 33 quality of life scales. Previous smokers had quality of life scores in between never smokers and continuous smokers. Smoking after treatment of head and neck cancer adversely influenced a wide range of quality of life endpoints. Quitters had better quality of life than patients who continued to smoke after treatment, suggesting that smoking cessation may improve quality of life in addition to reducing the risk of new cancer.