Malnutrition is a health problem which affects a high percentage of old people since the physical and psychosocial changes common to this period of life favor it in this group. In addition, aging population has a high prevalence of chronic illnesses and acute pathologies which can affect their nutritional state negatively, leading to malnutrition related to illness.

The aim of this systematic revision was to analyze the economic costs related to malnutrition in old people and to discover whether there were differences between economic costs of pre-existing malnutrition prior to illness and malnutrition because of disease.

A bibliographic search was carried out in the databases of Pubmed, Web of Science and Scopus, for the period between 2000 and 2016.

A total of 1,001 articles were found and 19 were selected using inclusion criteria. Of these, eleven analyzed the costs of pre-existing malnutrition prior to illness, seven analyzed the costs of malnutrition related to illness and one, both situations.

In general, malnutrition increased health costs as a result of hospital admissions, greater number of readmissions and greater demand on health resources. Moreover, in the studies analyzed, pre-existing malnutrition prior to illness implied greater costs than those related to the actual illness; therefore, it would be convenient to establish selection and preventive policies on malnutrition in old people.