Purpose of reviewMalnutrition is highly prevalent in hospitalized patients. Despite this, it is not routinely assessed in most hospitals worldwide. One of the reasons that might explain this fact is that there is no gold-standard nutritional assessment tool, and much has been written advocating this or that technique. The main topic of this review is discussion of the advantages and disadvantages of each of the available tools.Recent findingsSeveral studies have recently reinforced the relationship between poor nutritional status and higher incidences of complications, mortality, length of hospital stay and costs. Therefore, it is of the utmost importance to be able to diagnose malnutrition early.SummaryThe evaluation of nutritional status is a broad topic that encompasses several clinical variables. In order to be ideal, the method should be able to predict patient outcome, should be able to be performed by most care-givers, should be inexpensive, and should not be time-consuming. Unfortunately, most nutritional assessment instruments were published with insufficient details regarding their intended use and method of derivation, and with an inadequate assessment of their effectiveness. Therefore, health professionals should be critical when defining which instrument should be adopted by an institution, and several factors should be taken into consideration.