Abstract:The fact that an enormous portion of the public revenue is lost through tax evasion indicates the inevitability of taking various measures to suppress it. According to the latest statistics, the outflow from the gross domestic product through tax evasion is 30%. The aim of this paper is to point to the systematisation of the matter relating to an assessment of the efficiency of tax audit as a pillar of the reduction of tax evasion and informal economy in our country. Methodology implies a descriptive research. Collected data were meticulously analysed by means of basic arithmetic operations. Due to serious consequences of tax evasion, it is necessary to upgrade the tax system modelled on developed market economies. It is necessary to modernise a Tax Administration, as well as to improve the co-operation between its segments. A synthetic income tax should be introduced. It would encompass all revenues that a taxpayer generates per year. If all taxpayers settled their tax liabilities, it would create space for tax burden reduction. In legal states only "the bravest" resort to tax evasion. Most countries have undertaken a series of measures in order to suppress tax evasion and informal economy. However, the effectiveness of the struggle varies.