With the entry of the Republic of Croatia into the European Union, we have opened the door for the introduction and withdrawal of funds from European funds. In the pre-accession negotiations we had the opportunity to get acquainted with the concept of projects funded from pre-accession funds. Now that we have so many opportunities to withdraw additional funds, we are facing a constant change in tax and accounting regulations in order to comply with the provisions of the European Union. Defining the conditions for recognizing eligible costs is regulated by each individual project. The problem arises when it comes to the moment of project implementation and in the meantime there have been changes in the laws and regulations that we did not count on. The difference between actual and planned costs can be classified as unplanned operating costs. Another issue to point out is the posting of a business event project. They are governed by the rules of budgetary accounting and a special ban on dual financing of the same expense (eg. Salary). The principle of cost-based rule applies in all situations when it comes to regular business, but in some EU project situations it is completely unacceptable. The aim of this paper is to get closer to the problem of budget users who are encountering EU project bookkeeping. This paper focuses on practical situations that are not contained in the guidelines that are available and published in some magazines or pages of the Ministry of Finance. Implementing and monitoring EU projects is a complex procedure where a wide range of legal regulations and regulations and the accounting profession are to be taken into consideration.