Malnutrition (undernutrition) remains one of the most serious health problems for older people worldwide. Many factors contribute to malnutrition in older people, including: loss of appetite, polypharmacy, dementia, frailty, poor dentition, swallowing difficulties, social isolation, and poverty. Malnutrition is common in the hospital setting, yet often remains undetected by medical staff. The objective of this review is to compare the validity and reliability of Nutritional Screening Tools (NSTs) for older adults in the hospital setting. We also provide an overview of the various nutritional screening and assessment tools used to identify malnutrition in hospitalised older adults. These include: Subjective Global Assessment (SGA), the Mini Nutritional Assessment (MNA), MNA-short form (MNA-SF), Malnutrition Universal Screening Tool (MUST), Simplified Nutritional Appetite Questionnaire (SNAQ), Geriatric Nutrition Risk Index (GNRI) and anthropometric measurements. The prevalence and outcomes of malnutrition in hospitalised older adults are also addressed.