51-year-old woman with short Roux limb misconstruction. For upper gastrointestinal examination, medium-density barium was administered through gastric tube in excluded gastric segment. Fluoroscopic image shows distal portion of stomach (asterisk) and biliary limb (arrowheads) are unremarkable. At distal anastomosis, preferential flow of contrast material into alimentary limb (white arrows) is evident with little contrast material passing distally into common limb (black arrow). Antegrade assessment of alimentary limb was limited owing to concomitant proximal anastomotic stenosis (not shown). At surgery, Roux limb measuring only 25 cm was identified. Short length allowed retrograde reflux, resulting in Roux-en-O physiologic characteristics.