The article determines that, at first glance, the legal regulation of the activities of an advocate in criminal proceedings is well regulated, complies with international standards and does not require any adjustment.
 The article determines that, at first glance, the legal regulation of the activities of an advocate in criminal proceedings is sufficiently regulated, complies with international standards and does not require any adjustment. However, as practice shows, many problems arise in the implementation of criminal procedural law based on conflicts and gaps in it. Among them, a major place is occupied by the problems of defense, representation and other types of professional legal assistance to participants in criminal proceedings by an advocate.
 The article examines the state of legal regulation of participation of an advocate in criminal proceedings to provide professional legal assistance to the participants of such proceedings. The authors analyze the absence of the right of the victim and his/her representative to engage an expert in criminal proceedings on contractual terms, other restrictions on the rights of the victim and his or her representative to collect evidence, the right to review the pre-trial investigation materials before its completion, no right to receive a copy of the notice of suspicion and indictment, no right to file a request to the investigating judge for temporary access to things or documents, as well as the right to appeal against a preventive measure applied to a suspect/accused on the grounds of its leniency, etc.
 The article also analyzes the rights of a representative of a civil plaintiff or a civil defendant in criminal proceedings in relation to the rights provided for by the Civil Procedure Code of Ukraine, the author draws attention to the need to provide representation for another owner or possessor of property in legal relations regarding the right to file a petition to cancel the arrest of property in whole or in part, and considers the procedural status of a witness's advocate and a whistleblower's advocate.
 The article proposes amendments to the provisions of the Criminal Procedure Code of Ukraine in the context of legal regulation of participation of an advocate in criminal proceedings to provide professional legal assistance to the participants of such proceedings.