Safe work processes and information systems are vital in health care. Methods for design of health IT focusing on patient safety are one of many initiatives trying to prevent adverse events. Possible patient safety hazards need to be investigated before health IT is integrated with local clinical work practice including other technology and organizational structure. Clinical simulation is ideal for proactive evaluation of new technology for clinical work practice. Clinical simulations involve real end-users as they simulate the use of technology in realistic environments performing realistic tasks. Clinical simulation study assesses effects on clinical workflow and enables identification and evaluation of patient safety hazards before implementation at a hospital. Clinical simulation also offers an opportunity to create a space in which healthcare professionals working in different locations or sectors can meet and exchange knowledge about work practices and requirement needs. This contribution will discuss benefits and challenges of using clinical simulation, and will describe how clinical simulation fits into classical usability studies, how patient safety may benefit by use of clinical simulation, and it will describe the different steps of how to conduct clinical simulation. Furthermore a case study is presented.