Investigating factors influencing the use of clinical information systems can help to develop a strategy to improve user acceptance of a given system or similar ones in the future. In this research, we investigated factors influencing the use of information technology in the emergency department (ED). We undertook a qualitative study in which data were collected using semi-structured interviews with the ED staff. In total, 34 interviews were conducted and data were analysed using framework analysis. The results showed that user characteristics and perception of task, technology, environment, and impact of technology could influence people's use of IT in the ED. Of these, the usefulness of the systems, the impact of technology, IT training, and the feasibility of using IT by all members of staff seemed to be the main concerns. Addressing these factors in designing and implementing a system could help to introduce the change successfully and improve the acceptance of information technology.