This paper is a critical edition of “Lament of the Death of Honourable Lady Katarzyna Branicka” (Treny na śmierć Jej Mości Paniej Katarzyny Branickiej, starościnej niepołomskiej) by Jan Achacy Kmita. The preface introduces the readers to the Kmita’s biography, provides a characteristics of his works and at the same time includes the historical literary analysis of the series of threnodies. The article contains of: The description of the source, which includes the reconstruction of title page, The critical apparatus along with Rules of transcription, and the transcription itself. The editor’s commentary explains the historical, biographical, and linguistics issues, together with the symbolism as well as references to the Ancient poetry and Old Polish literature (mythology, the Bible, works of Jan Kochanowski, “The Aeneid” by Publius Vergilius Maro). The glossary contains of the words that might be unclear for a contemporary reader. The purpose of the critical edition of “Lament of the Death…” is to facilitate the readings for a contemporary reader for whom the vocabulary and old phraseology is more ambiguous and to encourage a greater number of readers to discover the compelling writings by forgotten Jan Achacy Kmita.