Skeletal muscle abnormalities are well-established in patients with heart failure from an early stage in the progression of the disease and contribute to their symptoms and the limitation of physical activity. Heart failure-induced skeletal muscle pathology includes morphologic, histologic, and enzymatic changes along with derangements in skeletal muscle metabolism and autonomic function. These alterations influence both peripheral and ventilatory muscles, are present at rest, and deteriorate during exercise and their occurrence depends upon the severity and the duration of CHF syndrome. Future studies will be needed to elucidate the origin of skeletal "myopathy" and its reversibility, which is associated with improvement in exercise capacity, observed after physical training programs.