Introduction: There is increasing attention to (disease) prevention within healthcare. However, in OECD countries only around 1% of health expenditure is spent on prevention. In the Netherlands different parties are responsible for organizing prevention. As a consequence, embedding preventive activities into the Dutch healthcare system lags behind. Especially for people with health risks, such as overweight children or frail older people. In order to move towards sustainable organized prevention, it is necessary that organizations start working together. In recent years several policy interventions have been introduced to stimulate cross-sector collaboration and the transition towards sustainable prevention infrastructure in the healthcare system. The aim of this study is to learn more form this transition. Who is it for? Researchers, policymakers, collaborative prevention networks. Methods: This longitudinal qualitative study was conducted among collaborative networks working together on integrating prevention, care and welfare to build a prevention infrastructure. Interviews were held with representatives of municipalities, health insurers, municipality health services and program managers. Two to five interviews per network were conducted during a five year study period. In total 88 semi-structured interviews were held. Networks were followed over time to gain insight into experiences with cross-sectoral collaboration. And to explore the changes in perceived barriers and facilitators associated with collaborating on implementing a prevention infrastructure. Key findings: Barriers for implementing a prevention infrastructure are unknown (cost-)effectiveness and differences in organization culture between municipalities and health insurers. Growing awareness of the urgency of prevention and acknowledgement of mutual responsibilities can be seen as a facilitator. As well as national policy interventions concerning a regional prevention infrastructure and a intervention-oriented approach. Preconditions for ...