Due diligence is carried out in the process of acquisition with the purpose of assessment and evaluation of the value of the targeted company and identification of possible risks in the process of take-over. There are several types of due diligence, but usually in practice financial, legal and commercial due diligence are done by hiring experts from related areas. The goal of this paper is to describe three key types of due diligence with the detailed overview of the financial due diligence. The accent is on the role of the auditor in the execution of the financial due diligence: legal frame, purpose, scope, conditions and details of the execution. This paper will outline the differences between the process of financial due diligence and the audit of financial reports. It will detect and analyse key reports, data and indicators in the process of financial due diligence, all supported by example from practice. The paper will also show carried out actions and documentation that the auditor is examining and analysing in the process of collecting the auditing evidence on which the audit report on the results of the done due diligence will be written and presented.