Acute limb compartment syndrome (ALCS) is defined as compound symptoms resulting from poor oxygenation and decreased nutrition supply to muscles and nerves in a tightly confined compartment. The most common cause of ALCS is tibia fracture, followed by blunt trauma to soft tissue. However, non-traumatic causes are rare. We report an iatrogenic, non-traumatic ALCS case after venoarterial extracorporeal membrane oxygen (VA-ECMO) therapy. A 14-year-old male received VA-ECMO therapy due to cardiorespiratory failure after drowning. Although he had no symptoms during therapy, leg swelling appeared 10 hours after ECMO treatment. Two days after the leg swelling, the patient underwent a fasciotomy. Unfortunately, nerve conduction studies and electromyography showed multiple neuropathies in the lower leg. Despite 2 weeks of rehabilitation with electrical stimulation, an exercise program, and physical therapy, there was no definite change in muscle strength. To our knowledge, this is the first reported case of non-traumatic ALCS after VA-ECMO therapy in Korea.