Background: It remains a continual challenge to present information in user interfaces in large IT systems to support overview in the best possible way. We here examine how an Electronic Health Record (EHR) supports the creation of overview among hospital physicians with a particular focus on the use of an interface designed to provide clinicians with a patient information overview. The overview interface integrates information flexibly from diverse places in the EHR and presents this information in one screen display. Our study revealed widespread non-use of the overview interface. We explore the reasons for its use and non-useMethod: We conducted exploratory ethnographic fieldwork among physicians in two hospitals and gathered statistical data on their use of the overview interface. From the quantitative data, we identified where the interface was used most and conducted 18 semi-structured, open-ended interviews framed by the theoretical framework and the findings of the initial ethnographic fieldwork. We interviewed both physicians and employees from the IT units in different hospitals. We then analysed notes from the ethnographic fieldwork and the interviews and ordered these into themes forming the basis for the presentation of findingsResults: The overview interface was most used in departments or situations where the problem at hand and the need for information could be standardised – in particular, in anesthesiological departments and outpatient clinics. However, departments with complex and long patient histories did not make much use of the overview interface. Design and layout were not mentioned as decisive factors affecting its use or non-use. Many physicians questioned the completeness of data in the overview interface – either because they were sceptical about the hospital’s or the department’s documentation practices, or because they could not recognise the structure of the interface. This uncertainty discouraged physicians from using the overview interface.