The problem of creating proper safeguards to ensure attorney-client privilege has always attracted the attention of lawyers, as this Institute is the basis of advocacy. The issues of preservation in secret from third parties information notified to the client in confidence to his attorney are solved first of all at the legislative level. Thus, the Russian legislation on advocacy and the legal profession establishes the legal profession as a fundamental basis for the profession of lawyers and also obliges lawyers to enforce it. Paragraraph 1 of Article 8 of the Federal Law of the Russian Federation "On advocacy in the legal profession in the Russian Federation", as well as p. 5 Article 6 of the Code of Professional Ethics of a lawyer determine the subject of the privilege. As a guarantee of its securing p.2 Article 8 of the Law on Advocacy indicates the impossibility of calling a lawyer and his interrogation as a witness about the circumstances that have become known to him in connection with the provision of legal assistance. In accordance with the legal position of the Constitutional Court of the Russian Federation on this issue, expressed in a number of decisions and definitions, the state is obliged to ensure at the legislative level and in law enforcement, such conditions for the exercise by citizens of the right to qualified legal assistance and for effective implementation by lawyers of activities to provide it, under which the citizen has the opportunity to freely disclose to the lawyer confidential information, and the lawyer in turn - the opportunity to prevent its disclosure. At the same time the requirement of confidentiality is the basis of a trust relationship between a lawyer and a client, covers any range of information provided both directly by the client and obtained independently by a lawyer during the provision of legal assistance and it is not limited in time. In the aspect of the above, the question of the possible limits, subjects and grounds for its disclosure, admissible criteria from the point of view of both legal and moral bases is very acute. The article focuses on the importance and relevance to the practice of law Institute attorney-client privilege, allowed its disclosure in light of changes in the existing criminal-procedural legislation, in particular, during the questioning of counsel, previously provided legal assistance in criminal proceedings with the aim of establishing procedural violations of investigative actions with his participation . The authors carry out a comparative analysis of the rules of legal and ethical regulation of this institution; generalize disciplinary practice of lawyer chambers of the subjects of the Russian Federation; emphasize the procedural contradictions in this aspect. The conclusions and proposals made in the work are aimed at improving the current legislation of the Russian Federation and law enforcement practice and can also be used in the educational process.