The effects of focused ultrasound have been investigated on the structures of electroreceptor system of the Black Sea skates (Raja clavata, Dasyatis pastinaca), as well as on the tissues of some other poikilotherms (fishes Belone belone and Solea lascaris, toad Bufo viridis, frog Rana temporaria). It was shown that focused ultrasound evokes excitation (onset of impulse activity) when applied to the pore of electroreceptors and inhibition of the activity when applied to the ampulla itself. The data obtained indicate that thermal conductivity of tissues in poikilotherms is lower than that in homoiotherms.