The subject of this final paper is how IT system is helping in the public procurement system in the Republic of Croatia. The aim is first to define the very concept of e-commerce and public procurement, and how it facilitates the process of public procurement to the participants. While proving the concept aim, concept of e-commerce is described and how it became an unavoidable part of the current and future business world. During defining public procurement the advantages and disadvantages of e-business are induced and how the process of public procurement is simplified with the highest goal that procurement procedures should become more transparent. Comparing public procurement in Croatia and in some EU countries public procurement procedures are analyzed (public procurement structure, systems, processes of public procurement). In order to clarify public procurement, one of the applications for publishing tenders in Croatia is described, also its development over the years, the benefits, way to use the services and how to access the future users.