The most common cause of small bowel obstruction is postoperative adhesion, and besides a hernia, metastatic or primary cancer and small bowel tumors are possible causes. Superior mesenteric artery (SMA) syndrome is a rare cause of upper gastrointestinal obstruction and is associated with debilitating conditions with marked weight loss. SMA syndrome results from the compression of the third part of the duodenum due to the narrowing of the aortomesenteric angle. We report a 28-year-old woman with SMA syndrome after acute gastroenteritis. Her stomach was severely dilated due to the duodenal obstruction and computed tomography showed the compression of the third portion of the duodenum by SMA. She was conservatively cared for and thus favorably improved.