The paper analyzes the lexical and textual features of the manuscript of the Kazan Gospel of the 14th century (the long lectionary of the so-called Mstislav type and class) preserved in the academic library of the Kazan Federal University. The research aim is to identify the manuscript's genetic relationships and to determine the range of closely related manuscripts on the basis of 25 different lexical markers. The authors have found out that the text of the Kazan Gospel reflects the vocabulary of various versions of the gospel text: archaic, Preslav, and Old Russian. In some cases old Slavic lexical units were already completely incomprehensible to the Russian copyist of the 14 th century that led to serious distortions of the text made by both Russian and Greek scribes. Besides, the lexical mistakes such as inserts into the text from parallel or similar fragments have been described and determined as an important factor for determining the nearest circle of related gospel copies. The authors conclude that the analysis of the manuscript's lexical features in isolation from its textual features is incorrect, and therefore it is proposed to consider both lexical and textual features of manuscript's versions, taking into account their structural features (in this connection a number of relevant markers are also highlighted).