With this thesis, I will attempt to explain what budget law is, what it generally encompasses, and its usual purposes. The subject matter of this paper is conceived on the state budget, which displays all the revenues and expenditures of a legal state. On the website of the Ministry of Finance of the Republic of Croatia, it is possible to see the revenue plan (e.g. various contributions paid into the state budget, different taxes, donations, fines etc.) and expenditures (e.g. various material and financial expenses, subsidies, allowances to citizens and households based on insurance etc.). The state budget is interesting in that its planning and approval can sometimes take longer than just the execution of the budget. It begins with planning, followed by its proposal, and subsequently the budget's approval. Only then does the actual execution of the budget occur, where budgetary funds can be spent as previously determined. An essential component in this entire process is budgetary control, which is carried out to ensure that budgetary funds are spent as previously decided. Tax control is thoroughly described in the Budget Law.