An 85-year-old malnourished man was admitted with ischemia-induced necrosis of the right leg and high-risk factors, including chronic obstructive pulmonary disease, pneumonia, and infection of the necrotic leg. We controlled the infection and provided proper nutrition. Using light general anesthesia and a nerve block, we amputated the leg above the knee. The patient could eat and drink the same day following the surgery, and respiratory rehabilitation was begun the next day. His postoperative course was uneventful. Our case suggests that maintenance of good nutrition may play a key role for high-risk elders undergoing leg amputation.