Methods of identifying malnutrition in the rehabilitation setting require further examination so that patient outcomes may be improved. The purpose of this narrative review was to: (1) examine the defining characteristics of malnutrition, starvation, sarcopenia and cachexia; (2) review the validity of nutrition screening tools and nutrition assessment tools in the rehabilitation setting; and (3) determine the prevalence of malnutrition in the rehabilitation setting by geographical region and method of diagnosis. A narrative review was conducted drawing upon international literature. Starvation represents one form of malnutrition. Inadequate energy and protein intake are the critical factor in the aetiology of malnutrition, which is distinct from sarcopenia and cachexia. Eight nutrition screening tools and two nutrition assessment tools have been evaluated for criterion validity in the rehabilitation setting, and consideration must be given to the resources of the facility and the patient group in order to select the appropriate tool. The prevalence of malnutrition in the rehabilitation setting ranges from 14-65% worldwide with the highest prevalence reported in rural, European and Australian settings. Malnutrition is highly prevalent in the rehabilitation setting, and consideration must be given to the patient group when determining the most appropriate method of identification so that resources may be used efficaciously and the chance of misdiagnosis minimised.