Malnutrition (undernutrition) is one of the many health inequalities facing governments in the 21st century. Malnutrition is a common condition affecting millions of individuals in the UK, particularly older adults, the sick and those cared for within the healthcare system. It costs the National Health Service >£7·3×109 annually. New data highlight marked geographical differences in the prevalence of malnutrition across England and an inter-relationship between deprivation, malnutrition and poor outcome. As malnutrition is a largely treatable condition, prompt identification and effective prevention and treatment of this costly condition is imperative. Routine screening for malnutrition in high-risk groups (e.g. the elderly and those in areas with high deprivation) and within the healthcare system should be a priority, with screening linked to appropriate plans for the management of malnutrition. Use should be made of specialised interventions, including oral nutritional supplements and artificial nutrition, to aid recovery and improve outcome, with skilled health professionals, including dietitians, involved where possible. Equity of access to nutritional services and treatments for malnutrition needs to occur across the UK and, although complex and multi-factorial, the effects of deprivation and other relevant socio-economic and geographical factors should be addressed. Ultimately, as malnutrition is a public health problem, its identification and treatment must become a priority for governments, healthcare planners and professionals.