This article investigates miscommunication in sequences of talk where an oncologist asks about patients' co-morbidities, that is, their other illnesses beyond cancer. Using conversation analysis, we examine ways in which the participants identify and manage two sources of miscommunication: a divergence in the doctor's and the patient's understandings about the scope of the question; and a divergence in the doctor's and the patient's (and sometimes their companion's) understandings about the matters that the question targets. Our findings have implications for practice, highlighting ways in which clinicians and patients can manage these sources of miscommunication. These include practices to retrospectively or pre-emptively manage ambiguities and to check the accuracy of patients' answers. Additionally, our study addresses some theoretical and methodological problems in the study of miscommunication. Our data consist of 25 video-recorded first consultations in an Italian hospital; the participants speak Italian.