Miniature endoscopes that can be introduced into the bile duct through the duodenoscope during endoscopic retrograde cholangiopancreatography were developed to allow nonsurgical management of difficult biliary stones. The direct visualization enabled by these cholangioscopes of the biliary epithelium provides additional data in the assessment of biliary strictures. Cholangioscopy allows assessment of the biliary lumen, biliary epithelium, targeted tissue acquisition, targeted therapy, and wire guidance.