The use of information and communication technology in public administration with the aim of increasing efficiency and effectiveness in the provision of public services and the functioning of internal processes on the one hand, and increasing the responsibility and transparency of administrative work on the other hand, is what constitutes e-government. E-government enables users to use its services in a fast, cheap and simple way and facilitates the internal functioning of the organization. The principle of administrative simplification aims to simplify and reduce regulations, simplify administrative procedures and implement a one stop shop system. A one stop shop can be organized as a point of physical or digital contact and can include a certain amount of services provided to citizens or entrepreneurs. In Croatia, a one stop shop is represented by the e-Građani [e-Citizens] system, defined as that part of the state information infrastructure which consists of the central state portal system, the national identification system and the user's personal mailbox system. This paper aims to present the development of e-government and the one stop shop system in Croatia on the specific example of the e-Građani (e-Citizens) portal; to review the portal's main components, as well as it advantages and potential improvement opportunities.