Older adults are at risk of protein-energy malnutrition (PEM). PEM detrimentally impacts on health, cognitive and physical functioning and quality of life. Given these negative health outcomes in the context of an ageing global population, the Healthy Diet for a Healthy Life Joint Programming Initiative Malnutrition in the Elderly (MaNuEL) sought to create a knowledge hub on malnutrition in older adults. This review summarises the findings related to the screening and determinants of malnutrition. Based on a scoring system that incorporated validity, parameters used and practicability, recommendations on setting-specific screening tools for use with older adults were made. These are: DETERMINE your health checklist for the community, Nutritional Form for the Elderly for rehabilitation, Short Nutritional Assessment Questionnaire-Residential Care for residential care and Malnutrition Screening Tool or Mini Nutritional Assessment-Short Form for hospitals. A meta-analysis was conducted on six longitudinal studies from MaNuEL partner countries to identify the determinants of malnutrition. Increasing age, unmarried/separated/divorced status (vs. married but not widowed), difficulties walking 100 m or climbing stairs and hospitalisation in the year prior to baseline or during follow-up predicted malnutrition. The sex-specific predictors of malnutrition were explored within The Irish Longitudinal Study of Ageing dataset. For females, cognitive impairment or receiving social support predicted malnutrition. The predictors for males were falling in the previous 2 years, hospitalisation in the past year and self-reported difficulties in climbing stairs. Incorporation of these findings into public health policy and clinical practice would support the early identification and management of malnutrition.