The purpose of this paper is to investigate the possible role of immunonutrition in head and neck cancer patients. Malnutrition frequently occurs in head and neck oncological patients, due to mechanical obstruction, such as tumour induced cachexia, poor dietary habits, as well as excessive alcohol consumption. These defects combined with the immune suppressive effects of surgery have been claimed to contribute in increasing the postoperative complications rate, such as poor wound healing and higher incidence of infections. Immunonutrition has been proposed to provide specific benefits to the immune system; several clinical trials, also in head and neck cancer patients, are already present in the literature, even if methodological differences impede comparisons and firm conclusions so far. Nutritional oncology is a new and interesting field and requires the use of standardised intervention protocols in order to evaluate its clinical efficacy.