Despite there being extensive cumulative knowledge and many experiences about factors that contribute to health Information Technology (HIT) success, lessons are yet to be learned as many HIT developments still face a number of problems - many of them of an organizational nature. This chapter presents a new method - the EUPHIT method – for studying and understanding one of the most crucial organizational success factors in HIT development: end-user participation. The method was developed and used for the first time throughout a research study of an EHR planning process in a Danish region. It has proved effective in disclosing the interactions that occur between the different social groups involved in HIT development, and in understanding the underlying reasons for these. This allows HIT project manage- ment to explore new avenues during the development process in order to support, facilitate, and improve real end-user participation.