Care home residents often lack access to end-of-life care from specialist palliative care providers. Palliative Care Needs Rounds, developed and tested in Australia, is a novel approach to addressing this. To co-design and implement a scalable UK model of Needs Rounds. A pragmatic implementation study using the integrated Promoting Action on Research Implementation in Health Services framework. Implementation was conducted in six case study sites (England, n = 4, and Scotland, n = 2) encompassing specialist palliative care service working with three to six care homes each. Phase 1: interviews (n = 28 care home staff, specialist palliative care staff, relatives, primary care, acute care and allied health practitioners) and four workshops (n = 43 care home staff, clinicians and managers from specialist palliative care teams and patient and public involvement and engagement representatives). Phase 2: interviews (n = 58 care home and specialist palliative care staff); family questionnaire (n = 13 relatives); staff questionnaire (n = 171 care home staff); quality of death/dying questionnaire (n = 81); patient and public involvement and engagement evaluation interviews (n = 11); fidelity assessment (n = 14 Needs Rounds recordings). (1) Monthly hour-long discussions of residents' physical, psychosocial and spiritual needs, alongside case-based learning, (2) clinical work and (3) relative/multidisciplinary team meetings. A programme theory describing what works for whom under what circumstances with UK Needs Rounds. Secondary outcomes focus on health service use and cost effectiveness, quality of death and dying, care home staff confidence and capability, and the use of patient and public involvement and engagement. Semistructured interviews and workshops with key stakeholders from the six sites; capability of adopting a palliative approach, quality of death and dying index, and Canadian Health Care Evaluation Project Lite questionnaires; recordings of Needs Rounds; care home data on resident demographics/health service use; assessments and interventions triggered by Needs Rounds; semistructured interviews with academic and patient and public involvement and engagement members. The programme theory: while care home staff experience workforce challenges such as high turnover, variable skills and confidence, Needs Rounds can provide care home and specialist palliative care staff the opportunity to collaborate during a protected time, to plan for residents' last months of life. Needs Rounds build care home staff confidence and can strengthen relationships and trust, while harnessing services' complementary expertise. Needs Rounds strengthen understandings of dying, symptom management, advance/anticipatory care planning and communication. This can improve resident care, enabling residents to be cared for and die in their preferred place, and may benefit relatives by increasing their confidence in care quality. COVID-19 restricted intervention and data collection. Due to an insufficient sample size, it was not possible to conduct a cost-benefit analysis of Needs Rounds or calculate the treatment effect or family perceptions of care. Our work suggests that Needs Rounds can improve the quality of life and death for care home residents, by enhancing staff skills and confidence, including symptom management, communications with general practitioners and relatives, and strengthen relationships between care home and specialist palliative care staff. Conduct analysis of costs-benefits and treatment effects. Engagement with commissioners and policy-makers could examine integration of Needs Rounds into care homes and primary care across the UK to ensure equitable access to specialist care. This study is registered as ISRCTN15863801. This award was funded by the National Institute for Health and Care Research (NIHR) Health and Social Care Delivery Research programme (NIHR award ref: NIHR128799) and is published in full in Health and Social Care Delivery Research; Vol. 12, No. 19. See the NIHR Funding and Awards website for further award information.