The purpose of this study was to determine the procedural guarantees provided to experts and specialists in the process of collecting and further studying documents as evidence in criminal proceedings. The study revealed that a document in the field of evidence in criminal proceedings can be both material evidence and a direct source of evidence. Thus, the main difference between these concepts is that an expert has the right to conduct an independent investigation, while a specialist has a rather limited function – to apply special knowledge in the course of a criminal investigation. The paper analysed the laws and regulations of Ukraine and the European Union concerning the definition of the rights of an expert and specialist in criminal proceedings, including the collection and use of documents as sources of evidence. The study highlighted the important role that experts and specialists play in ensuring the integrity and reliability of evidence, emphasizing the need for reliable procedural protection of their rights. The practical significance of this study lies in its potential use by researchers for a deeper investigation of the problems of ensuring the procedural rights of experts and specialists in criminal proceedings.