Chronic heart failure (CHF) is a disease most prevalent in the elderly. Additionally, symptoms are often aggravated in this population because of an overlap between the physiological age-related decline in exercise capacity and the disease-related functional decline. This study aimed to asses the effects of exercise training on endothelial progenator cells (EPCs) number and function in young and older CHF patients. It was found that 4 weeks of aerobic exercise training are effective in increasing EPCs number and function in young and older CHF patients.