The role of SIASG/Comprasnet in promoting efficiency and transparency in government procurement (GP) in Brazil has generated great interest in the international scenario of e-commerce and in the transformation of public administration, related to the e-government initiative. Several international organizations and some national governments have elected this experience as a best practice in e-government in the government-to-business (G2B) classification. Some of the innovations implemented by the system are the use of the e-reverse auction (e-RA) and the publishing of information of all the phases of the tendering process. This chapter has the aim of analyzing the results obtained by the Brazilian government strategy in the use of a specifically developed e-government procurement (e-GP) system (http://www.comprasnet.gov.br). It is composed of a structuring system, operated internally by the government, coupled with a Web interface for suppliers and the general public that covers the whole GP cycle (including post-award contract administration) of commodities (sundries and standard quality goods and services). The analyzed e-GP application accounts for expenditures of around $8.5 billion. This amount is equivalent to 15% of the budget (1.5% of GDP).