Abstract: This article is devoted to the nettlesome issues of tax consulting and tax expertise of commercial organisations. The subject of the research is the financial relations arising between the state, business and tax consultant as the actors of such relations. The object of the research is the tax expertise, tax analysis and tax audit in particular. The author of the article provides a detailed description of the object under research including the contents, theoretical and practical approaches to the matter, and covers the relationship between tax consulting, tax expertise, tax analysis and tax audit. Baburyan pays special attention to the method of tax expertise. The research is based on general methods such as comparison, analogy, classification, generalisation, analysis and synthesis, and expert evaluation method. The author's special contribution to the topic is his classification of tax expertise depending on several features and the methods of complex tax expertise and added value expertise developed by him. The novelty of the research is caused by the fact that the author compares definitions of the object under research and makes a conclusion about their similarity and difference.