Cholangioscopy was first performed in the 1970s. We now use the term cholangiopancreatoscopy (CP) to reflect the wider application of these miniature reusable dual-operator “mother-daughter” endoscope systems and now fully disposable and digital single-operator optical catheters for evaluating the biliary or pancreatic duct. Cholangioscopy is an established modality for the management of large biliary stones and for the diagnosis and exclusion of biliary tumors. Pancreatoscopy is increasingly being performed to treat difficult pancreatic duct stones and may be used to distinguish malignant from benign ductal pathology. This review covers available CP technologies, indications, technique, efficacy, and complications.