Annular pancreas (AP) is a congenital anomaly and a recognised cause of duodenal obstruction which can affect all age groups. It may manifest early in the neonatal period, but it may also have varied and often delayed symptoms. We report the case of AP in an 18-month-old girl with a long history of recurrent post-prandial non-bilious vomiting treated for a long time with the clinical diagnosis of gastroesophageal reflux. Upper gastrointestinal study was suggestive of partial duodenal obstruction and computed tomography revealed a complete ring of pancreatic parenchyma surrounding the second part of the duodenum. Diamond-shaped duodenoduodenostomy was achieved successfully and the post-operative period was uneventful. Although rare, AP must be kept in mind of any paediatric surgeon while confronted to symptoms of partial duodenal obstruction.