The article tries to analyze and classify the diplomatic instruments, ie documents and acts used in the process of the activity of the embassy of Moldova principality in the 15th-17th centuries. It is found that the instruments used in the diplomatic practice of the embassy of Moldova principality largely coincided with the customs of international relations in Europe (except for the final report). First of all, the presence of acts directly related to the activity of the embassy, the so-called indispensable diplomatic tools, is noted. On the basis of these documents, he was the representative of the prince and the empowerment given to him to deal with certain matters – the letters of passage and the letter of accreditation, without which the embassy could not function and did not have the character of a diplomatic mission. The other documents (the instructions, the correspondence etc.) can be labeled as optional ones, they did not necessarily accompany the embassy and their lack did not disturb the activity of the embassy.