Sarcopenia refers to reduced muscle mass in the elderly population, and this malady is of great interest in clinical course, including postoperative complications and mortality when treating major cancer in the elderly. The definition of sarcopenia varies according to the method of measuring muscle mass, and the skeletal muscle index (SMI) tends to be extensively used in retrospective studies. In many reports, sarcopenia has been reported to be a poor prognostic factor after gastrectomy, colectomy, pancreatectomy and liver transplantation, with regards to complications and the length of the hospital stay. Additionally, patients suffering from sarcopenia have a higher medical burden due to their poor clinical outcome after surgery. To overcome these difficulties, nutritional support and exercise training to improve sarcopenia before surgery is helpful, and so further studies that focus on these treatments need to be conducted.