The paper presents current knowledge of the role of selenium in the development of cardiovascular system disease (CSD). Already known mechanisms of selenium action in the cardiovascular system are described, whilst underlining the fact that they do not explain all relevant observations and need to be clarified by more studies. Clinical, epidemiological, and experimental studies devoted to the relationship between the progression of CSD and selenium status indices are then reviewed. It could be expected that any explanation of the pathophysiological mechanisms of the influence of tobacco smoking (as one of the classical risk factors for CSD) on selenium status might help to bring about a better understanding of the progression of cardiovascular disorders. Based on studies conducted on animal models, the role of selenium in the antioxidant defense of cardiac muscle is described. Particular attention is paid to a dilated cardiomyopathy known as Keshan disease, for which it has been shown that selenium deficiency is an environmental factor predisposing to the onset of this disease. Similar symptoms of cardiomyopathy are also observed in patients on total parenteral nutrition and patients with AIDS.