The author of the article examines one of the “technical” characteristics of the insufficiently studied social phenomenon — private correspondence in Russia of Early modern time. The analysis shows that the methods of sending private letters largely depended on the class accessory of correspondents. A significant part of the private correspondence was forwarded by the serfs, and that this class or at least a large portion of it, was a very mobile part of the population, almost equivalent in this respect to other social groups in Russia in the XVII century. At the same time, representatives of the highest class groups for sending correspondence widely used opportunity. There was the bureaucratic hierarchy in the choice of couriers for sending letters by noblemen. The higher the rank of the sender was, the wider was the range of officials, representatives of which could play the role of a courier for sending letters on occasion.