Due diligence is a process by which various aspects of the subject of due diligence, most commonly business, are being checked to find the information you need and to gain confidence in the information presented. Due diligence is a process that has a given methodology of detection, processing and control of information, and begins by preparing the list of questions and requests for document delivery. It ends with a report which has multiple purposes: it represents the basis for calculations, analysis, and decision-making; it is the basis for the preparation of legal acts and it is used as a good basis for the management board decision making process. The purpose of this paper is to present the areas covered by due diligence; to determine what is the subject of due diligence and what type of information is gathered during due diligence process. The need for due diligence usually arises as a result of an acquisition or investment process, public offers, changes in management or restructuring. The working methodology is based on risk assessment, and covers different areas that enable indepth understanding of the subject of takeover; such as understanding the key drivers of revenue in the past, how was EBITDA realized in previous years, provides an answer to the question whether the value of the net assets is over- or undervalued, and which are other relevant occurrences and transactions. Due diligence is performed by a multidisciplinary team of consultants, because the knowledge needed is covered by different areas. Key areas explored through the due diligence process are history and ownership, management and organization, financial information, market, competition and customers, manufacturing process, real estate, plant, equipment and intangible assets, loan and borrowing liabilities, working capital and taxes. With its scope it is a prerequisite for effective integration.