Background: Chronic kidney disease (CKD) and kidney failure (end-stage kidney disease - ESKD) become more common as people age. They increase the risks of other major illnesses and sudden death. Even so, many people with ESKD do not discuss their preferences for end-of-life care with their families or healthcare professionals. Advance care planning (ACP) can help patients and families think through their preferences for future care and discuss these with the professionals looking after them. This may lead to care more in keeping with patients’ wishes and so reduce distress for patients and families. Consequently, ACP is recommended as good practice for people with ESKD. However, we still need to find out more about the impact of ACP on patients and families; and also about the best ways to put it into practice. This study is designed to test the research methods for a larger study that would answer those questions. Aim: To determine the feasibility of conducting a deferred entry RCT, alongside a mixed methods study, to evaluate ACP with older patients who have ESKD. Objectives are to investigate: acceptability of the ACP intervention to patients, their carers and professionals; optimal intervention systems for delivering ACP; recruitment and retention rates; randomisation procedures; suitability of survey instruments and outcome measures; time needed to collect and analyse data; effect sizes that might help inform sample-size estimates and methods for assessing cost effectiveness in a full trial. Methods: Denying the opportunity for ACP would be unethical, so 40 patient/carer dyads will be randomised in a 12 week RCT to immediate or deferred entry groups to allow between group comparisons, before the deferred entry group proceeds to ACP. Intervention processes will be followed through using observational and qualitative methods for 12 months or to bereavement if sooner, to identify key factors for implementation success.