Double Bubble sign is a classical radiological sign commonly seen in duodenal atresia. It is often observed in infants as dilatation of proximal duodenum and stomach, giving an appearance of two bubbles ( hence double Bubble). Other uncommon causes may include: Duodenal stenosis Midgut volvulus Superior mesenteric artery syndrome Annular pancreas Choledochal cyst Ref: Reeder Maurice Merrick and Benjamin Felson. Reeder and Felson's gamuts in radiology. Springer, 2003. ISBN: 0387955887, 9780387955889.