The aim of the article is to study the long-term translation studies activity of P. Kulish based on the epistolary sources material stored in the funds of the Institute of Manuscripts of V. I. Vernadsky National Library of Ukraine (hereinafter – IM NBUV), and Chernihiv State Literary-Memorial Museum of Mykhailo Kotsyubynsky (hereinafter – CSLMMMK). In a broad culturological context, the significance of his translation studies activity for the prerequisites of forming the Ukrainian literary language is highlighted, but at the same time, he is distinguished by his own translation style and the author’s handwriting. All names of documents and their content, which are contained in library and museum institutions, are presented in the original language, and without any spelling changes. Research methods. This article grounds on general scientific methods of analysis and synthesis, which involved historical, systematic, typological and aesthetic ones, as well as methods of archival and source-based heuristics, source studies criticism, textual analysis of sources and information reconstruction. The combination of these scientific methods makes it possible to analyse in detail the activity of P. Kulish in the field of Ukrainian translation studies. The scientific novelty of the study consists in highlighting the epistolary sources (manuscripts of letters, diary, telegrams) that are stored in the archives of the IM NBUV, and which reveal the translation studies work of P. Kulish. In particular, they point to a significant amount of available documents that testify to the artist’s titanic activity in the process of translating works of European and world literature classics into the Ukrainian language. First of all, the process of translation and publication of V. Shakespeare’s works is described in detail from the corpus of epistolary sources specified in this research. Main conclusions. A large number of P. Kulish’s letters, more than one and a half thousand epistles, is accumulated in the IM NBUV funds. The presented set of archival documents shows one of the many creative interests of P. Kulish, the artist’s translation activity during all his life. This can be proved by the writer’s correspondence and all the documents related to this topic found in NBUV. The epistolary of P. Kulish is scattered among twelve funds of the scientific institution, and is a valuable informational resource that indicates the significance of the translator’s scientific and creative work. CSLMMMK funds also contain a considerable number of archival documents (both letters and translation manuscripts) that directly highlight the translation activity of P. Kulish. A large block of documents related to the writer’s name is concentrated in the fund of his wife, Hanna Barvinok. This is mainly the epistolary heritage of the artist, who corresponded with many correspondents of P. Kulish, particularly, after his death. It is well known to publicity that that P. Kulish translated thirteen dramas of V. Shakespeare, but archival documents show a different statistics. Thanks to Hanna Barvinok’s letters, in which she repeatedly noted that P. Kulish translated fifteen dramas of V. Shakespeare, other figures can be ascertained. However, apart from P. Kulish’s epistles, no other relevant archival material has been found yet, that could testify to the words of the artist’s wife. The information component of Shakespeare’s themes is most widely represented in the correspondence of the translator himself. Especially, this applies both to the translation process itself, and to the printing of works in general.