The article is devoted to the study of the issue of using open-source evidence in criminal proceedings. Attention is drawn to the lack of a universally recognized definition of the term “open-source information”, a list of fundamental features of this type of information is provided, among which are: 1) accessibility of the information to the general public; 2) the author of the information may not be determined; 3) access to information can be provided both on a paid and free basis. The lack of an adequate volume of legislation aimed at regulating the procedure for usage of open-source evidence is emphasized. A study of the Berkeley Protocol, which was created jointly by the University of California, Berkeley School of Law and representatives of the United Nations, was carried out. In particular, the following is outlined: a list of the principles enshrined in the Berkeley Protocol, divided into professional, methodological and ethical, their content; the investigation process put forward in the Berkeley Protocol, that consists of the following stages: 1) online inquiries; 2) preliminary assessment; 3) collection of information; 4) preservation of information; 5) verification of information; 6) investigative analysis. Problems that may arise in the process of using open-source evidence are emphasized. The requirements of propriety, admissibility and reliability of open-source evidence are studied. The state of legal regulation of the issue of the usage of open-source evidence in national legislation is considered. The specific features of electronic (digital) evidence are singled out, which distinguish them from other types of evidence and determine the need to separate them in the criminal procedural legislation as a different type of evidence. The practice of national and international judicial institutions related to the use of open-source evidence is considered. The special role of this type of evidence for establishing the corpus delicti or circumstances of crimes against the foundations of national security, especially since the beginning of full-scale Russian aggression against Ukraine, is emphasized.