The subject of this paper is the design and development of a public procurement information system. A special attention is paid to the public procurement information system in the Republic of Serbia and to its possible improvements. The first part of the paper deals with the public procurement information system and its significance, while the second part deals with the modeling of the public procurement processes. As an original contribution to the paper, the two schematic representations are provided, which can help in the development of the information system - the scheme of electronic public procurement process and the scheme of necessary functions that e-procurement software should have in order for the information system to function successfully. The final result of this research is a critical presentation of a software solution that enables efficient public procurements.