Design in healthcare projects is complex because of the high number of stakeholders and the involvement of end-users in the design process. This causes collaboration issues and information asymmetry which are barriers in communication and information exchange. The purpose of this research is to gain insight into the design process in healthcare building projects, more particularly into the way the end-users groups like the medical caregivers and the design team exchanged information and participate in developing the design. The focus of this research is the end-user design team interactions in the hospital design process. The main research question is: In hospital building projects, how does the project organization translate the end-user information into design? By performing a single case study, data was collected through context analysis, document analysis, and in-depth interviews about end-user involvement, information flow, and decision-making process in Erasmus MC Rotterdam new building project. Ten interviews were conducted with different members of the project organization including project managers and leaders, design experts, and also external advisors. The research analysis illustrates a participative design and decision-making process and the three main findings of this research:(1)End-users from different groups were involved in the design and decision-making process and the level of involvement was different in each stage. There is mainly a consultative form of user involvement that evolved into a co-design form in the technical phase of design. User representatives and designers were members of technical design teams: TOTs in this phase looking for design solutions together. (2) Two groups had key roles during the process: User Coordinators and the Building Expertise group. User Coordinators ensure the gathering of user information and engagement of end-users during the design, and they are the information exchange link between the end-users and the design team. The Building Expertise group in this project had an intermediator role acting in different boundaries of the organization. (3) Design decisions are based on continuous consultation with end-user representatives which are linked to the project organization at all levels. There was a transparent and informed decision-making process. Review matrices were decision-making support tools used by different groups including different end- end-user groups and help different groups exchange information in different boundaries. Research findings and the analysis gives a better understanding of information management, end-user, and stakeholder management in healthcare building design and planning and give insights on project management and how to organize the information exchange and the team interactions and use different methods and tools during the briefing and design process in complex building design projects like hospitals.