Primary sarcopenia is considered to be age-related when no other cause is evident, other than aging itself. Secondary sarcopenia should be considered when one or more other causes are evident, such as multiple chronic conditions. Previous studies have reported that low muscle strength and impaired physical performance can be found in chronic diseases, including metabolic disease (diabetes, hypertension, and obesity), arthritis, osteoporosis, cancer, chronic kidney disease, chronic obstructive pulmonary disease, neuromuscular disease, and chronic infection. The development of preventive and therapeutic strategies against secondary sarcopenia and wasting disorders in general is an epidemiological need. The planning of a complex rehabilitation program in sarcopenia associated to chronic conditions, in the context of a comprehensive treatment, is made up of a nutritional support, exercise, correction of lifestyles, and the use of advanced physical energies. Therefore, for the purposes of the optimal management, it is essential to identify the pathogenesis and clinical characteristics that can affect the different rehabilitative treatment.