Myopathy is a general term referring to any disease that affects the muscles that control voluntary movement in the body. Patients experience muscle weakness due to a dysfunction of the muscle fibers. Some myopathies are genetic and can be passed from parent to child. Others are acquired later in life and can be due to autoimmune disease, known as myositis, metabolic disorders or other causes. Myopathies are a group of disorders that are characterized by a primary structural or functional impairment of the skeletal muscle. These diseases usually affect muscles without involving the nervous system, thus resulting in muscular weakness. The latter represents one of the most common complaints among patients presenting to family physicians or neurology specialists. Nevertheless, fatigue, exercise intolerance, and myalgias can also occur in a plethora of non-myopathic conditions. Therefore, a comprehensive evaluation of each patient should include a thorough examination and a combination of adequate laboratory, radiologic, electrodiagnostic, and pathologic studies.