Annular pancreas is a rare congenital intestinal obstruction to be found in infants. It is characterized by nonbilious vomiting, abdominal distention, and feeding intolerance that share similar symptoms with other intestinal obstructions. We reported a case of 11-month-old female infant with a history of nonbilious vomiting after coughing as much as 6 times per day 1 day before admission. The patient had an incorrect provisional diagnosis of hypertrophic pyloric stenosis based on ultrasound. Later on, an upper gastrointestinal series showed dilatation of the second part of the duodenum which was successfully treated by a duodenostomy during laparotomy procedure. It is suggested that treating an intestinal obstruction needs a further investigation when the symptoms were continuously repeated.