The aim of this paper is to show the impact of physical activity on reducing the incidence of myocardial infarction and death from its consequences and the role of physical activity in treatment and rehabilitation. Cardiovascular diseases are a significant public health problem in the world and are the main cause of death in developed countries. In Croatia, cardiovascular diseases are also the leading public health problem and according to data from the Croatian Institute of Public Health, a myocardial infarction is one of the most common single causes of death. Previous studies have proven that a healthier way of life, namely lifestyle changes and the control of risk factors, through the activities of primary and secondary prevention, reduces morbidity and mortality from cardiovascular disease. Physical activity is a key factor in preventing disease and maintaining health, but the treatment and rehabilitation after a myocardial infarction is also of fundamental importance. Engaging in physical activity after a myocardial infarction begins in organized and supervised programs in specialized institutions and continues on an outpatient care basis in accordance with the health status of the patient. Physical activity is an essential part of the strategy for improving health in the world and in Croatia.