Skeletal muscle abnormalities and loss are frequently present in patients with mild or moderate cardiac heart failure (CHF) and may contribute to fatigue and dyspnea. These muscle abnormalities may be associated with age related body composition changes, such as sarcopenia. Muscle damage has also been observed in subjects with cardiac cahexia, a serious CHF complication, associated with poor prognosis independently of functional disease severity, age, and measures of exercise capacity and cardiac function. Loss of muscle mass is a feature of cachexia, whereas most sarcopenic subjects are not cachectic. Individuals with no weight loss, no anorexia, and no measurable systemic inflammatory response may be sarcopenic. Patients with severe CHF show multiple marked histological abnormalities of skeletal muscle, such as muscle fiber atrophy. These abnormalities are different in sarcopenia and cachexia. The majority of mechanisms involved in sarcopenia play a role even in the determination of cachexia and they are amplified in cachexia where they may induce both muscle damage as well as other abnormalities, such as fat and weight loss, through activation of lypolisis or anorexia. To distinguish cachexia and sarcopenia in CHF patients, even if not easy, should be clinically relevant, because no specific treatment is available for cachectic patients whereas treatment options are possible for sarcopenia.