Survival rates for head and neck cancer are comparatively poor, typically 40% at 5 years. Radiotherapy is one of the most common modalities used to cure early-stage cancers. It has the advantage in that it preserves anatomical structure and function. However, treatment failures do occur necessitating salvage surgery if a cure is to be achieved. A universally accepted definition of radioresistant cancer does not exist. Second primaries and occult metastasis are common in head and neck cancer, and can be confused with true radioresistant tumours. We suggest a strict definition for radioresistant laryngeal cancer and characterize 66 radioresistant tumours stage matched to 66 radiosensitive tumours. It was not possible to differentiate the radioresistant group from the radiosensitive groups using tumour differentiation. By using an agreed set of criteria defining radioresistant head and neck tumours, researchers will be better able to investigate molecular and cellular markers of radioresistance.