Effects of a pulsed-modulated superhigh frequency field (950 MHz, peak power of 300 mkW/cm2 and 1.5 mW/cm2, pulse duration of 1 ms, single pulse irradiation mode, a pause between an electromagnetic pulse and an optic or auditory stimulus--20 ms) on the cat's brain evoked potentials were investigated in the optic, auditory and sensomotor cortex using acoustic and visual stimulation. It was established that during an exposure to electromagnetic waves with peak power of 300 mkW/cm2 there were no reliable changes of the amplitude characteristics; but the amplitude of the auditory evoked potentials was reliably higher and the amplitude of the optic evoked potentials was reliably lower when they were affected by an electromagnetic field with peak power of 1.5 mW/cm2.