Organ preservation with radiotherapy and concomitant chemotherapy has become an accepted treatment modality in advanced head and neck cancer. Unfortunately, organ preservation is not synonymous with function preservation. The aim of this review was to systematically assess the effects of the disease and chemoradiotherapy (CRT) on functions such as swallowing, mouth opening, nutrition, pain and quality of life in patients with head and neck cancer. Another aim was to search for (evidence-based) techniques or strategies known to alleviate or rehabilitate the loss of function(s) associated with CRT. Two databases were searched (time period, January 1997 to August 2007) for the terms head and neck cancer, chemotherapy or cisplatin and radiotherapy, and the functional outcomes swallowing, trismus, nutrition, pain and quality of life or a variation of those words. In total, 15 relevant articles were identified that met the inclusion criteria. The majority of the studies that met the criteria focused on the outcomes swallowing, quality of life, and nutrition. Two studies reported on the outcome pain, but no paper reported on the outcome trismus. Only two papers mentioned rehabilitation options, but specific information was lacking. Further long-term prospective research is essential, not only to determine the function impairment caused by the tumor and CRT, but also to assess the effects of known and newly developed rehabilitation measures. Therefore, in September 2006, the Netherlands Cancer Institute started a randomised clinical trial (RCT): Prevention of trismus, swallowing and speech problems in patients treated with chemoradiotherapy for advanced head and neck cancer. This systematic review was carried out to collect the baseline information for the future outcomes of this RCT.