The thermovision has been used for investigation of the myocardium function. In cardiosurgery it is important to know how the cut off in blood supply affects the muscle function. The aim was to investigate relations between ischemia and myocardium temperature and to prove that the ischemic zones (IZ) can be determined by thermography. Results. Experiments were performed on dogs. In the areas of ischemia thermograms and EG were recorded. The data showed that the temperatures in the IZ and the border zone of ventricular myocardium were different from healthy myocardium. The evaluation of temperature changes in the IZ were performed by using a specially created package of programs. A analysis of the thermograms showed that between the IZ and healthy myocardium a border zone is formed. The zone is several millimeters wide, and its temperature is by 1C higher than in healthy myocardium. The dynamics of temperature measured at all points of the ischemic zone has been shown. The correlation between myocardium temperature and the characteristics of EG recorded in the IZ has been shown. Conclusion. The data show that thermography is the method for determination of the IZ and the border zone in ventricular myocardium. Thermography gives a possibility to evaluate the function of myocardium and the ischemic damage of myocardium during surgery.