Objective - to identify the morphological equivalents of the cardiotoxic action of organophosphate poisoning. It was studied 110 fatal organophosphate poisonings in toxicogenic and somatogenic stages. The study of the heart was a comprehensive in term of clinical, biochemical, histological, micromorphometric, histochemical and histoenzymological approaches. We have identified a complex of deep metabolic disorders and necrobiotic changes in the heart muscle and the level of cholinesterase activity inhibition in the cholinergic structures of the heart in the toxicogenic and somatogenic stages of fatal organophosphate poisoning.