Background. The transport layer is designed to deliver data without errors, losses and duplication in the order in which they were transmitted. It provides data transfer between two applications with the required level of reliability. Transport layer protocols, which guarantee reliable data delivery, establish a virtual connection before data exchange and resend segments in case of loss or damage. The aim of the study was to determine the role of transport security protocols in computer networks. Materials and methods. To achieve the goal, the study used statistical analysis and a systematic approach. Results. TCP provides reliable message transmission through the formation of logical connections, while allowing peers on the sending computer and the receiving computer to support data exchange in duplex mode. It also has the ability to seamlessly send a byte stream generated on one of the computers to any other computer connected to the network.In addition, TCP controls the connection load, UDP does not control anything but the integrity of the received datagrams. Conclusion. The difference between TCP and UDP is the so-called "delivery guarantee". TCP requires a response from the client to whom the data packet is delivered, confirmation of delivery, and for this he needs a pre-established connection. TCP is also considered reliable, unlike UDP, which is called "unreliable datagram protocol". TCP eliminates data loss, duplication and shuffling of packets, delays, UDP allows all this, and it does not need a connection to work., as a result of which the data is transferred on UDP, should manage received, even with losses.