The paper discusses theoretical and practical aspects of calculating depreciation of fixed assets in the Republic of Serbia. The aim is to investigate the practice of calculating depreciation of fixed assets in enterprises in the Republic of Serbia in order to determine the possible failure (irregularities) that may affect the overall quality of financial reporting. Correct calculation of depreciation of fixed assets provides a realistic representation of depreciation expenses in the income statement and real value of fixed assets in the balance sheet. Based on the research conducted, the paper will reveal systemic irregularities in calculation of depreciation of fixed assets. In this sense, we believe that the content of the paper and conclusions arising from it will encourage accountants in various companies to change the way of calculating depreciation of fixed assets.