The article is devoted to consideration of the issue of transposition in the Ukrainian-language reproduction of texts in the international legal sphere. The research is conducted in two stages. During the first stage, the importance of translating international legal documents into Ukrainian is defined. The main requirement for the translation of texts in the international legal sphere is also defined, namely: to accurately convey the content of legal documents in the target language. It is found that the translation of international legal documents is an integral component of the development and improvement of the Ukrainian terminological system in the international legal sphere. It is established that Ukrainian linguists deeply study the English-language terminology of the legal sphere because of the development of the legal system in English-speaking countries. Definitions of the concepts “international law” and “international legal documents” and their categories and types are also characterized. It is clarified that international legal documents have legal force, therefore the definition of the concept of “legal documents” and their features are also defined: the definitions of legal terms are not always fixed in lexicographic sources, for the terms of the legal sphere, the division into inter-branch and intra-branch terms is unacceptable, legal terms can be used not only in a professional context, but also in everyday communication. During the second stage, the concepts of affixation and conversion are analyzed. The main components of affixation are also found out. Additionally, the definition of the concept of “transposition”, its levels (complete or morphological and incomplete or syntactic), as well as its classification, are presented. It is also found that transposition has three components: the transposed, the transpositor, and the transpose. 10 types of transposition are presented: substantivation, verbalization, adjectivization, pronominalization, prepositionalization, numeralization, adverbialization, conjunctionalization, particulation, and internalization. 10 sentences of the English-language text from the European Convention on Human Rights and their Ukrainian translation are analyzed and classified according to 7 types of transposition: substantivation, verbalization, adjectiveization, pronominalization, prepositionalization, adverbialization, and particulation. During the analysis of examples of translation by means of numeralization, conjunctionalization and internalization in the texts of the European Convention on Human Rights, no examples are found. The research material is the European Convention on Human Rights [7], [8] and the scientific work of E. Koval, 2020 [9].