Objectives: Describing what simulation centre leaders see as the ideal debriefing for different simulator courses (medical vs. crisis resource management (CRM)-oriented). Describing the practice of debriefing based on interactions between instructors and training participants. Methods: Study 1 -Electronic questionnaire on the relevance of different roles of the medical teacher for debriefing (facilitator, role model, information provider, assessor, planner, resource developer) sent to simulation centre leaders. Study 2 -Observation study using a paper-and-pencil tool to code interactions during debriefings in simulation courses for CRM for content (medical vs. CRM-oriented) and type (question vs. utterance). Results: Study 1 -The different roles were seen as equally important for both course types with the exception of 'information provider' which was seen as more relevant for medical courses. Study 2 -There were different interaction patterns during debriefings: line -involving mostly the instructor and one course participant, triangle -instructor and two participants, faninstructor and all participants in a dyadic form and net -all participants and the instructor with cross references. Conclusion: What simulation centre heads think is important for the role mix of simulation instructors is (at least partly) not reflected in debriefing practice.