We present the results of studies of the electromagnetic radiation (EMR) shielding by epoxy-nanocarbon composites (CMs). The EMR frequency range was 25.5-37.5 GHz. Thermoexfoliated graphite and multiwalled carbon nanotubes (CNT) have been used as fillers in CM (the content of a filler was 0.5-2 wt.%). We examined the effect of carbon filler's type in CM on characteristics of the electromagnetic shielding. It is shown that, even for low contents (similar to 1-2 wt.%.) of a nanocarbon filler in CMs, the coefficient of EMR transmission is -(25-27) dB (for h = 1 mm). The real epsilon' and imaginary epsilon '' parts of dielectric permittivity of the composites under investigation have beet? determined.