Malnutrition is common in neurodegenerative disorders and is associated with a worse prognosis and an increased risk of complications. Factors leading to malnutrition in these patients are: diseased nutrient intake, due to anorexia, dysphagia and other factors, gastrointestinal symptoms, and energy expenditure alterations. Nutritional evaluation and monitoring is mandatory and should be part of regular clinical evaluation. It will help to identify those patients that need specialized nutritional support. In this paper, relevant aspects regarding nutritional evaluation and support in patients suffering from a neurodegenerative disorder are reviewed, including amyotrophic lateral sclerosis, multiple sclerosis, Parkinson's disease and dementia.