Auditing in the Republic of Moldova is exercised in the form of external audit, performed by audit firms or individual independent auditors, and internal auditing, performed by a specialized department of an organization. Finite common goals of both types of audit are very similar – it is control. However, there are significant differences in the content and nature of their activities. Compared with the external audit, internal audit has a different nature, meaning, purpose and organization. Because of the generally accepted definition of internal audit task is to assist organizations in the effective discharge of their duties and assignments, then there is a management tool, designed to ensure (guarantee) the achievement of management objectives. Selecting objects for an audit depends on the specifics of the economic entity. A significant amount of audit work carried out by the auditor, it is necessary to test the mass of the current primary documentation. This circumstance is one of the justifications for the use of audit sampling methods of control. Audit sampling is the application of audit procedures to less than 100% of the items in the balance of the account or group of transactions in such a way that all elements of the sample can be selected. This will allow the auditor to obtain and evaluate audit evidence about the individual characteristics of the selected elements in order to formulate a conclusion or to facilitate its establishment in regard to the general population from which the sample is drawn.