OBJECTIVE:The purpose of this study is to identify the major challenges to coordination between emergency department (ED) teams and emergency medical services (EMS) teams. DESIGN:We conducted a series of focus groups involving both ED and EMS team members using a crisis scenario as the basis of the focus group discussion. We also collected organizational workflow data. RESULTS:We identified three major challenges to coordination between ED and EMS teams including ineffectiveness of current information and communication technologies, lack of common ground, and breakdowns in information flow. DISCUSSION:The three challenges highlight the importance of designing systems from socio-technical perspective. In particular, these inter-team coordination systems must support socio-technical issues such as awareness, context, and workflow between the two teams.