During design of the modern complex systems today more attention is paid to the reliability aspect. The traditional approach, which is based on redundancy techniques, is not always acceptable, because as a result the complexity and total cost of the developed project will increase. Therefore development of alternative approaches to increase the reliability of the designed systems is very actual task.

One of such approaches to increase the reliability parameter of the designed digital device (DD) during synthesis of digital automates is elementary coding of internal states of DD. But it has the combinatorial nature of the calculations and it is hardly possible to use existed tools in the situation of big value of the operational word width. In this paper the evolutionary approach to elementary coding of internal states of the state machine, which describes the functionality of the designed DD has been considered.