Background: Antimicrobial resistance (AMR) is a major public health problem. Elderly residents in long-term-care facilities (LTCFs) are frequently prescribed antibiotics, particularly for urinary tract infections. Optimizing appropriate antibiotic use in this vulnerable population requires close collaboration between NHS healthcare providers and LTCF providers. Objectives: Our aim was to identify and quantify antibiotic prescribing in elderly residents in UK LTCFs. This is part of a wider programme of work to understand opportunities for pharmacy teams in the community to support residents and carers. Methods: This was a retrospective longitudinal cohort study. Data were extracted from a national pharmacy chain database of prescriptions dispensed for elderly residents in UK LTCFs over 12 months (November 2016-October 2017). Results: Data were analysed for 341536 residents in LTCFs across the four UK nations, from which a total of 544796 antibiotic prescriptions were dispensed for 167002 residents. The proportion of residents prescribed at least one antibiotic over the 12 month period varied by LTCF, by month and by country. Conclusions: Whilst national data sets on antibiotic prescribing are available for hospitals and primary care, this is the first report on antibiotic prescribing for LTCF residents across all four UK nations, and the largest reported data set in this setting. Half of LTCF residents were prescribed at least one antibiotic over the 12 months, suggesting that there is an opportunity to optimize antibiotic use in this vulnerable population to minimize the risk of AMR and treatment failure. Pharmacy teams are well placed to support prudent antibiotic prescribing and improved antimicrobial stewardship in this population.