Superior Mesenteric Artery Syndrome (SMAS) is an upper intestinal obstruction due to the compression of the third duodenum between the Superior Mesenteric Artery and the Aorta. We report the case of a boy aged 14 years, with a BMI 12.49 kg / m², who presented for 10 days of postprandial bilious vomiting with persistent epigastric pain. Radiological assessment allowed the diagnosis of Superior Mesenteric Artery Syndrome with a 9° angle between the Aorta and the Superior Mesenteric Artery. Conservative treatment combining parenteral and enteral feeding came up with good results: we noted a gain in weight of 1 kg in 4 days, oral feeding was started and all symptoms disappeared. The patient was released after a 10-day hospitalization. Superior Mesenteric Artery Syndrome usually presents in its acute form, consisting of symptoms of upper intestinal obstruction. Severe weight loss is usually involved. CT scan allows the measurement of the Aorto-Mesenteric angle confirming the diagnosis. Conservative management is the first line treatment, if it fails, one can resort to second-line surgery.