Magnetic resonance cholangiopancreatography (MRCP) uses MR imaging to visualize fluid in the biliary and pancreatic ducts as high signal intensity on T2-weighted sequences: it is the newest modality for biliary and pancreatic duct imaging. MRCP is of proven utility in a variety of biliary and pancreatic diseases, including choledocholithiasis, congenital anatomic variants, chronic pancreatitis, post-cholecystectomy disorders, and neoplastic duct obstruction, MRCP is an evolving technique, but it has reached the stage of development where it is clinically useful and of comparable accuracy to conventional cholangiography. With further progress, it is likely that by the start of the new millennium MRCP will replace diagnostic endoscopic retrograde cholangiopancreatography as the modality of choice for imaging the biliary and pancreatic ducts. J. Magn. Reson. Imaging 1999;9:157-162, (C) 1999 Wiley-Liss, Inc.