To develop an advance care planning intervention based on the needs of patients with chronic kidney disease, families and healthcare professionals. Patients with chronic kidney disease and their families request early advance care planning that continues throughout their illness trajectory. Healthcare professionals experience barriers to initiating advance care planning. Involvement of stakeholders in development of health interventions is important, to identify priorities, understand the problem and find solutions. The development was inspired by the Medical Research Council's framework, and codesign was applied. One future workshop and one design workshop were conducted with the consumers. The process was iterative, and data were analysed using the action research spiral. The Guidance for reporting intervention development studies in healthcare (GUIDED) was used. Five areas were considered significant to an advance care planning intervention; a biopsychosocial approach, early palliative care, a family-focused approach, early and continuous advance care planning and a consumer-centred approach. Based on these, a conversation process with healthcare professionals was designed to give patients and families the opportunity to share values, preferences and wishes for treatment and their family and everyday life. Codesign facilitated a collaborative process that allowed the consumers to have a significant impact on the design of an advance care planning intervention. A conversation process concerning everyday life, illness and treatment was designed for patients and families. The intervention included an advance care planning tool to guide the healthcare professionals. The intervention has the intention to improve the communication between healthcare professionals, patients and families. The study provides important knowledge about the significance of giving the patients and their families support in sharing their values, preferences and wishes for treatment and everyday life, thus, to improve care and treatment in their illness trajectory. What problem did the study address Patients with chronic kidney disease and their families strongly request early initiation of advance care planning that continues throughout the illness trajectory. Healthcare professionals experience barriers to the initiation of the advance care planning and request a more systematic approach. What were the main findings Development of a conversation process about everyday life, illness and treatment for patients diagnosed with chronic kidney disease and families, including an advance care planning tool to guide the healthcare professionals. Where and on whom will the research have an impact The study contributes an advance care planning intervention to patients in the early stages of chronic kidney disease and their families. We believe that the intervention could be included during consultations with healthcare professionals in other stages of chronic kidney disease as well as other chronic disease. To strengthen the reporting of the development of the advance care planning intervention, we used the Guidance for reporting intervention development studies in healthcare (GUIDED). The development of the intervention in this study was a collaborative process between patients, families, healthcare professionals and representatives from the Danish Kidney Association, the department's user council and the research team.