Trust or, conversely, distrust users of audit reports in their content depends to a large extent on the quality of services provided by auditors. It is assumed a priori that the services provided by a financial auditor correspond in terms of quality, because in his work, every professional must strictly abide by a set of principles set out in the Code of Ethics, among which is found the principle of competence professional and due care. Despite the existence of this assumption, the International Auditing Standards contain three distinct standards aimed at ensuring the basic human reglamentarea audit: ISQC 1 - Quality Control it like for firms that perform audits and reviews of financial statements and other assurance and related services; ISA 200 - The overall objectives of the independent auditor and an audit in accordance with International Standards on Auditing; ISA 220 - Quality control for an audit of financial statements.