The prevalence of malnutrition, which is relatively low in free-living elderly persons (5-10%), is considerably higher (30-60%) in hospitalized or institutionalized elderly persons. As a result, nutritional assessment should be part of routine clinical practice in elderly patients who are frail, sick or hospitalized. A comprehensive screening tool for assessment of nutritional status is needed that is clinically relevant and cost-effective to perform. A number of simple and rapid tests for detecting or diagnosing malnutrition in the elderly have recently been developed. If malnutrition is suggested by such screening tests, then they should be supplemented by conventional nutritional assessment before treatment is planned.