The article looks at tax expenditures as a type of government spending classified as off-budget expenditures. The authors examine the influence of this form of government spending on the Polish budget. Tax expenditure is the revenue that a government foregoes through special tax credits, deductions, exclusions, exemptions, deferrals, and preferential tax rates. Tax expenditures reduce the tax burden in order to achieve specific tax policy goals. The focus on preferential tax structures is especially important now that many countries are struggling with imbalances in their public finance sectors and are grappling with growing public debts, the authors say. The overall estimated value of tax expenditures in Poland in 2011 amounted to $24.5 billion, according to the authors, while the general government deficit that year was $19 billion. This illustrates the scale of off-budget public spending, the authors say. In 2009–2011, tax expenditures accounted for 16.65% to 19.23% of total public spending, according to the authors, and the loss of government revenue was estimated at between 27.7% and 29.6% of state tax revenue. However, this part of public spending is not always transparent, the authors say. It evades public control and effectively limits the possibility of pursuing a responsible fiscal policy.