Afferent loop necrosis after Roux-en-Y cholangiojejunostomy biliary reconstruction is rare. We present the case of a 36-year-old woman with acute necrotic afferent loop obstruction. The peripheral area of the Roux-en-Y limb, including the cholangiojejunostomy portion, was twisted just proximal to the cholangiojejunostomy. Cholangiojejunostomy was completely separated due to necrosis of the Roux-en-Y jejunum. In addition to the case report, we discuss features of cholangiojejunostomy that require special attention.