The effect of passive smoking by the rabbits on the metabolism of myocardium was studied in three experimental models: following a single instance of smoking (for a period of thirty minutes); following a two-week smoking (twice a day for thirty minutes each); following an eight-week smoking (twice a day for thirty minutes each, i. e. for a period of 56 days. In isolated mitochondria of myocardium a decreased respiration, oxidative phosphorylation rates and cytochromoxidase activity were observed both after a single-instance smoking and prolonged smoking. The above disorders are closely related to the energy production in myocardium. Based on comparison of the above metabolic disorders with the changes in ultrastructure and myocardial function (described in the literature) the authors have come to the conclusion that the term "smoker's cardiomyopathy" which may develop in habitual smokers is well justified. This kind of cardiomyopathy may participate in the development of cardiac insufficiency even in the absence of atherosclerotic changes in the coronary arteries.