Financial statements are written reports that give a structured presentation of the financial position, business performance, cash flows and other information about a company. Financial statements should be clear and transparent, fair and truthfull, i.e. realistically and objectively present the economic and financial state of the company. The purpose of the audit is trust in the financial statements, because if the financial statements have been audited, then these reports are more trusted than those that were not subject to some form of audit supervision. Users of information, creditors, investors, managers, brokers make decisions based on financial statements, therefore the statements must be reliable. By studying the financial statements, creditors make decisions about the riskiness of lending to the entrepreneur, his eventual over-indebtedness or inability to repay the loan. Future investors make decisions about the profitability ofinvestments as well as to assess the risk factor of investing in shares, while the information contained in financial statements helps managers in planning and making business decisions. This final thesis will analyse audit opinions that preceded the discovery of manipulations with financial statements. We will try to give an answerto the question of whether the auditors were able to expose fraudulent actions and, with their opinion, warn of possible manipulation of financial statements.