Under normal thermal conditions, hypertensive NISAG rats are characterized by lower plasma levels of high-density lipoproteins and increased coefficient of atherogenicity compared to normotensive Wistar rats. Slow cooling significantly modified fractional composition of plasma lipoproteins in hypertensive rats: decreased the content of low-density lipoproteins, markedly increased the content of high-density lipoproteins, and normalized coefficient of atherogenicity. Our results demonstrated the possibility of correcting disturbances in lipoprotein spectrum in essential hypertension by using thermal exposures.