The Scientific Archive of the Institute of Archaeology of the National Academy of Sciences of Ukraine holds a drawing of the tombstone of Prince Dmytro Kozeka. The drawing on a sheet of paper was made in pencil in the late nineteenth and early twentieth centuries. It contains two inscriptions (epitaphs) in Old Ukrainian and Latin and the princely coat of arms between them. The texts of the inscriptions were published twice in the nineteenth century. The large coat of arms on the tombstone has never been described. Its image, as well as the image of the inscriptions, is published for the first time. The large coat of arms has the shape of a heraldic shield inscribed in a circle. The shape of the shield is made in the Baroque style. Four heraldic signs are symmetrically arranged on the shield, the first of which, in the form of a bow and cross, is the minor coat of arms of the prince. This sign is present on the personal seals of Dmytro Kozeka. The second sign is still unknown in the heraldry of Ukraine in the sixteenth century. Two other signs belong to well-known arms used by many noble families. The paper is accompanied by illustrations that show a complete drawing of the prince’s tombstone and individual elements of this lapidary monument: two epitaphs and a great coat of arms, opening the way for studying the vocabulary of the inscriptions and performing paleographic analysis. The attribution of the coat of arms will allow us to clarify the genealogy of the Kozeka family. Prince Dmytro Kozeka died in 1583 and was buried in the Church of the Assumption of Our Lady in the monastery not far from Zymne village near Volodymyr city. The marble slab on the grave was installed by his wife Kateryna Falchevska. After the turn of the nineteenth and twentieth centuries, there is no evidence of the location of the slab. The Kozeka family appeared in Volhynia in the mid-fifteenth century. Their origin is not clear. Dmytro Kozeka is the most famous representative of this family, according to written sources. The paper describes some episodes of his biography, gives an overview of the princely estates, specifies the time period when his father died, and reveals the previously unknown names of his two sisters. The tombstone of Prince Dmytro Kozeka is a valuable historical source for the study of the elite stratum of the Ukrainian population of the early modern period.