Choledochal cysts are an uncommon anomaly of the biliary system; findings include cystic dilatation of the extrahepatic biliary tree, intrahepatic biliary tree, or both. In the past 7 years, 13 patients with choledochal cysts have been seen at the authors' institution for evaluation and presurgical intervention. Percutaneous transhepatic cholangiography (PTC) was performed in 13 patients. Sixteen percutaneous biliary drainage (PBD) procedures were performed in 11 patients, computed tomography was performed in six patients, and ultrasound was performed in two. PTC proved to be an important imaging modality because of its superior ability to define the cyst anatomy, site of biliary origin of the cyst, and extent and detail of both extrahepatic and intrahepatic disease, that is, intraductal strictures and calculi. PBD proved valuable in preoperative intervention, as an aid in surgical reconstruction, and in postoperative care. The role of these two modalities in the diagnosis and treatment of patients with choledochal cysts, in addition to clinical aspects of the disease, is discussed.