This paper deals with ISA 570 which refers to going concern. Going concern is one of the basic assumptions which needs to be assessed during financial reports preparation. According to that assumption, the business of the entity that prepares the financial reports will continue in the foreseeable future. It has been determined how it applies to a deadline of at least 12 months. The manager has the responsibility to assess the appropriateness of this assumption. The auditor's task is to evaluate management's assessment and verify the appropriateness of the assumption. This is true even in cases where management has failed to do so. The auditor should also consider whether there are significant uncertainties and risks associated with events and circumstances that could bring into question the continuing indefinite nature of the business. If they exist, it is necessary to check whether this is stated in the notes to the financial reports. It was found that the lack of analysis of the adequacy of the assumption of indefinite operation of the auditor, does not necessarily prevent the conclusion. The auditor can also use special models to assess the adequacy of the assumption, of which this paper deals with the yellow flag model, mathematical model and forensic financial analysis. Each of the models has its own characteristics, advantages and disadvantages compared to other models and analytical procedures of the auditor. The final product of the audit, is the audit report and the auditor's opinion. In relation with this assumption, the auditor may issue a positive opinion with a point to emphasize certain issues, an opinion with reservation and a negative opinion. The paper also presents two examples of audit opinion that showed that the opinion consists of certain sections, and these are the opinion, the basis for the opinion and the significant risks and uncertainties. The final conclusion reached in the preparation of this paper, emphasizes the importance and complexity of the auditor's task in assessing the adequacy of indefinite operations.