Thermal and electrical conductivities in composites (CMs) based on. various types of polymer matrix epoxy resin (epoxy) and polyethylene oxide (PEO) have been investigated in. the temperature range 150-300 K A few types of carbon materials have been used as a filler in CMs: thermoexfoliated graphite (TEG) (TEG content was 0.5-10 wt.%), TEG dispersed in an ultrasonic disperser (nano-TEG) (content - 1-2 wt.%), and multiwalled carbon nanotubes (MWCNTs) (content - 1-10 wt.%). It was shown that the ultrasonic dispersion of TEG in the epoxy matrix leads to a shift of the percolation transition in the electrical conductivity to higher values of the graphite content and decreases the thermal conductivity of these CMs. This occurs due to the break down of the worm-like structure of TEG particles, i.e., the already formed fragments of TEG clusters. It is revealed also that the use of epoxy as a polymer matrix and a nondispersed thermoexfoliated graphite as a filler gives the greatest values of the thermal and electrical conductivities of composites in the comparison with others.