In this work, we have tried to show how tax revenues have behaved in the State budget from 2003 to 2006. To address this question, we began by defining the concepts associated with taxation. We then analysed the impact of tax revenues on the State budget. Our aim here was to describe the tax process used by the tax authorities to fund the Treasury's general account in order to meet its budgetary obligations. Nevertheless, it must be admitted that tax revenues are the main budgetary resources in the Democratic Republic of Congo, when tax revenues are combined with customs revenues, because of the nine border ports that the DRC has throughout the country. This calls for even more seriousness and diligence on the part of tax officials and the authorities, as we have already suggested in our previous proposals, to develop major strategies to deal with the new forms of tax evasion and avoidance that are significantly reducing tax revenues.