By using an information processing and social identity approach, this study examines the relationships between the complexity of the health care needs of a patient and (1) the interactions among physicians during team meetings and (2) how the meeting participants evaluate the discussion. Three dimensions of the complexity of the health care needs are related to the interactive behaviour of medical specialists during meetings of multidisciplinary medical teams. Three medical teams from a Dutch university hospital, each discussing a total of 40 patients, were observed. The results show that component complexity was positively related to the amount of information team members exchanged, to positive reactions, and to the positive evaluation of the discussion. Two other dimensions (interrelatedness of needs and ambiguity) have to be considered in concert: interrelatedness was positively related to negative reactions but only if ambiguity was low; and, further, ambiguity was positively related to evaluative behaviour and to positive reactions, and negatively to the evaluation of the discussion, but only if interrelatedness was low.