The research relevance is determined by the growing role of Scopus and Web of Science as key tools for evaluation of scientific activities and the need to optimise the processes of forming collections and determining the subject areas of scientific journals to increase visibility and influence in the global scientific space. The study aimed to analyse the peculiarities of forming collections and determining the subject areas of scientific journals indexed in the international scientometric databases Scopus and Web of Science. Research methods included analysis and synthesis, systematisation and generalisation of data, as well as content analysis of scientometric databases Scopus and Web of Science, used to identify the specifics of the formation of collections and subject areas of scientific periodicals. The criteria for the selection of periodicals, the structure of subject areas and the specifics of the formation of collections in Web of Science were addressed. Differences in approaches to the classification of scientific journals by subject areas were analySed, and the impact of these differences on the representativeness of scientific research in various fields of knowledge was investigated. The main trends in the development of collections and subject areas of scientific journals in the context of modern requirements for scientometric indicators and international standards of scientific communication were identified. The study demonstrated that the Scopus and Web of Science databases have different approaches to classifying subject areas. The study determined that Scopus is characterised by a wider coverage of journals, especially in the social and medical sciences, while Web of Science emphasises journals with a high impact factor. The classification of subject areas is also different, which should be accounted fur during search and analysis of scientific sources. The practical significance of the study is determined by empirically grounded data on the formation of journal collections and subject areas in Scopus and Web of Science, which will contribute to optimisation of publication strategies, increasing research visibility, and improving the evaluation of scientific contribution, therefore beneficial for researchers and postgraduate students

classification; research; publications; impact factor; scientific communication