Printer’s mark (signet) is a trademark that the printer printed on books and with which it can be identified. As a typographic feature of a printer’s/individual title, it appears already in the very beginnings of printing. In addition to the role of an identifier, its function was also protection against forgeries, since the printing of books was an expensive and complex process, but also communicative as documents, information, visual representation or messages expressed through symbolic representation. Since the 16th century, when the title page took on its present-day features, typographical element is almost always found in the same place - centered in the middle of the page below the title and author’s name, and above the name of the printer, the place and year of printing, as well as the permission to print ( if it is stated), and the motifs that appear in artistic expression are diverse. The authors of the printer’s mark are mostly unknown, so it is assumed that they were mostly printers. After a historical review of the earliest appearance of printing marks in Croatia and Europe, and a presentation of some of the printing marks of the most important European printers, paper presents research on printer’s marks carried out on digitized Croatica (works by Croatian authors, works printed in Croatia, works that talk about Croatia and Croats) on a sample of 44 units of library materials stored in the fund of the National and University Library in Zagreb printed in Latin letters, from the 16th, 17th and 18th centuries. The aim of the paper is to draw attention to the printer’s mark as a rare or almost non-existent independent subject of research among Croatian scholars, due to its importance in the study of book history. The research brings the names of the printers of works by Croatian authors (Croatica), the systematization of printing marks grouped into 9 groups according to artistic motifs, as well as information on the existence of mottos. The idea of ambiguity of the name of a printing mark, which as such should be associated with a certain book in a situation where printers continuously use the same mark for all works, is also put forward, which indicates that the printing mark assumes the function of a logo.