Topicality. The urgency of this problem is determined by the necessity of developing a methodological support for operations due diligence for the domestic professional practice (in the field of accounting, auditing, taxation, finance and law) for the objective presentation of the investment object. Aim and tasks. The aim of the article is to study essence and methodical principles of professional service due diligence. Development of the author's approach to the content of the guidelines and criteria for the due diligence at winemaking enterprises. Research results. Due diligence has become relevant in our country as a service perspective for the development of the domestic audit industry. However, despite the growth of its prevalence in our country, this service has neither a clear definition nor standards, therefore, it needs to streamline its methodology and more formalization. The article reveals the essence and methodical principles of conducting the due diligence service. The author's approach to the content of the directions and criteria for carrying out the due diligence examination at the winemaking enterprises is shown. Conclusions. The results of study theoretical foundations, methodology and history of the due diligence procedure allowed us to define the due diligence procedure as a deep and comprehensive analysis of all aspects of the financial and economic activity of the enterprise: organizational, legal, financial, marketing, tax, political, market, technological, and others. in order to provide an objective idea of the object of investment. The results of the study of information sources on the practical experience of implementing the due dilinges procedure indicate that this examination is carried out in such general areas as: accounting, financial, legal, organizational, tax expertise and specific areas: verification of the company's information environment, compliance with the requirements of law enforcement in areas of environmental protection, company position in the market, analysis of political risks. The peculiarities of the functioning of enterprises, in particular winemaking enterprises, require the completion of the due diligence procedure in such areas as: vineyard characteristics, natural conditions, agronomical characteristics of plantations, quality of grapes, quality of wine materials, quality of finished products.