BACKGROUND weight loss is commonly observed in head-neck cancer patients, affecting 75-80% of them during their treatment period; weight loss is severe in 30-50% of cases. According to ESPEN publications, nutritional assessment in cancer patients should be frequently performed and nutrition support therapy must be started when any deficiency is observed. OBJECTIVE to evaluate the effect of early nutrition support (ENS) in nutritional markers and treatment response in patients with head-neck cancer receiving radiotherapy (RT). METHODS one hundred and two patients with head-neck cancer and more than two points in the malnutrition screening tool (MUST) before receiving RT were included. ENS was provided to all patients consisting in nutrition counselling, oral supplements and/or enteral nutrition. RESULTS one hundred and two patients were included; 76% had a stage IV of disease. At the end of RT, after ENS, a slightly decreased body mass index (BMI) with an increased fat-free body mass was observed (p < 0.001); biochemical nutrition parameters remained stable despite decreased oral intake. Less than 40% of patients had severe epithelitis or mucositis; 92% of patients received the total amount and doses of originally planned RT sessions, while 22.8% required RT-sessions interruption. Patients with caloric malnutrition had a lower fulfillment of RT than those without caloric malnutrition (p < 0.001). Mortality was related to lower Karnosfsky, higher weight loss before RT and higher grade of mucositis/epitelitis (p < 0.05). CONCLUSIONS patients who receive ENS keep their nutritional condition instead of associated effects due to RT. ENS represents an efficient treatment and could prevent malnutrition associated comorbidities in oncologic patients.