Unintentional weight loss and Undernutrition are major problems among older people living in Long-Term Care Facilities (LTCF). Undernutrition manifests in LTCF particularly as weight loss and low Body Mass Index (BMI) and is associated with increased morbidity and mortality as well as with functional decline. There are many factors associated with poor nutritional status and affecting protein-energy intake and/or energy expenditure. These include age of 85 years or older, low nutrient intake, loss of ability to eat independently, swallowing and chewing difficulties, becoming bed-ridden, pressure ulcers, history of hip fracture, dementia, depressive symptoms and suffering from two or more chronic illnesses. Nutritional evaluation is an essential part of the Comprehensive Geriatric Assessment (CGA). This evaluation ranges from methods such as BMI to several validated tools such as Mini-Nutritional Assessment (MNA). After diagnosis, the management of undernutrition in LTCF requires a multidisciplinary approach which may involve dietary and environmental improvements and managing multiple co-morbidities, while avoiding polypharmacy as far as possible. Finally, the need for supplementation or artificial (tube) feeding may be considered taking into account the CGA and individual needs. This document presents a succinct review and recommendations of evaluation and treatment of undernutrition.