This diploma thesis conceptually explains the budget, which is not only one of the key budgetary mechanisms of the Republic of Croatia, but also a unit of local and regional self-government. The budget is a planned presentation of revenues and expenditures for a certain period of time, contains the general and special part, as well as the plan of development programs. In addition to the concept of budget, the paper explains in more detail the budget classifications that provide management information and in many ways have the characteristics of the structure of managerial accounting. We divide budget classifications into program, economic, organizational, functional, locational and sources of financing. Budget classifications significantly ensure transparency of the budget and its execution. Organizational classification is established by formulating divisions, chapters, and budget users. Program classification is established by defining programs, activities and projects, and functional classification includes expenditures by purpose. The economic classification shows revenues and receipts by natural species and expenditures and expenses according to the purpose they serve. The location classification shows expenditures according to budget levels, which can be national, regional or local. Sources of financing show revenues from which certain types and purposes of expenditures are covered. The paper analyzes budget classifications and their role in budget management on the example of the budget of the City of Kutina.