Fasciola hepatica infection may result in biliary obstruction with or without cholangitis in the chronic biliary phase. Because clinical symptoms and signs of F. hepatica are similar to other biliary diseases that cause bile duct obstruction, such as stones or bile duct malignancies, that are, in fact, more common, this condition may not be suspected and diagnosis may be overlooked and delayed. Patients undergoing endoscopic retrograde cholangiopancreatography or endoscopic ultrasonography for the evaluation of bile duct obstruction may be incidentally detected with the worm, and diagnosis can be confirmed by extraction of the leaf-like trematode from the bile duct. Intraductal ultrasonography (IDUS) can provide high-resolution cross-sectional images of the bile duct, and is useful in evaluating indeterminate biliary diseases. We present a case of biliary fascioliasis that was diagnosed using IDUS and managed endoscopically in a patient with acute cholangitis.