Summary: Malnutrition is an essential problem in the older population. It is related to poor prognosis, increasing the risk of infections, hospitalization length, and convalescence duration as well as mortality rates. Despite that, it is often underdiagnosed and untreated. Elderly people are particularly predisposed to malnutrition. The article discusses general principles of older people’s nutrition care, up-to-date criteria of malnutrition diagnosis, and guidelines for the prevention and treatment of protein-energy malnutrition.