In the testaments of the merchants from Dubrovnik are mentioned numerous business-commercial registers, which the merchants led in their business in Dubrovnik, in the Balkan-hinterland and Italy. This fact also shows, to what extent the literacy was spread in Dubrovnik, from the business register themeselves is evident the improvement of the register-keeping in Dubrovnik. The majority of the private commercial registers arose from the registration of doing business on credit, the management of commercial companies, as well as from other purposes. Most of these business registers got lost, only a few have been kept. In the report, which is temporarily limited to the XIV. century, the emphasis is laid on the outside description of those registers, on their kind, their legal value and implementation in the commercial doing business.