Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disorder that causes progressive muscular weakness, severe weight loss, and ultimately death. Gastrostomy or nasogastric tube is beneficial for ALS patients with severe weight loss and dysphagia. However, the development of superior mesenteric artery (SMA) syndrome in ALS patients when the enteral feeding time is delayed is rarely reported. We report herein the first case of SMA syndrome in a Korean ALS patient who showed improvement after percutaneous endoscopic gastrojejunostomy(PEGJ).