In industrialized Countries malnutrition is a very frequent condition in frail groups of the population, people with low income and elderly subjects above all if institutionalized. The aim of the study is to: analyse the prevalence of malnutrition in a sample of elderly people located in different geographical areas in Italy; identify the psychological, social, economic, environmental, cultural and demographic determinants of malnutrition. The prevalence of malnutrition (estimated through the MNA) is high in both sexes (28% of F and 21.9% of M. Age, institutionalisation, health status, autonomy status, cognitive status and education level are some of the factors that correlate with the presence of malnutrition. Loneliness and poverty seem to have a negative impact on nutritional status but further data are needed to confirm this hypothesis. The data collected confirm the need to activate services dedicated to assess the nutritional status of elderly people, to implement campaigns in particular on food education for the elderly population, to set tools and guide lines for caregivers.