While the choice of access route is frequently determined by the expertise available in the institution, guidelines as to which approach should be used when both techniques are available are slowly becoming established (Figure 1). The first consideration in selecting the method of access is the presence of coagulopathy. If the patient's platelet count is less than 50 × 106/L or if the international normalized ratio (INR) is 1.4 or greater, the risk of attempting PTC is greatly increased. In this situation, either endoscopic access to the biliary tree can be used or the coagulopathy can be corrected prior to PTC. If the patient's platelet count and INR are within the normal range, then the choice of the access route depends on 2 major factors: the caliber of the bile ducts and the location of the biliary disease. In most cases, patients with biliary disease have already undergone either ultrasonography or computed tomography, the results of which determine the size of the intrahepatic bile ducts. If ductal dilatation is present, then either PTC or ERCP can be performed without difficulty. In normal-caliber ducts, PTC is technically difficult and ERCP is usually preferred.1 The second consideration in choosing an access route is the location of the biliary pathologic lesion. Lesions in the distal common bile duct are more easily accessed using ERCP, while biliary hilar or intrahepatic lesions are more easily approached using PTC.1 Lesions in the mid–common bile duct can be readily approached with either access method. Taken together, consideration of the expertise available at the institution, the presence of coagulopathy, the caliber of the intrahepatic bile ducts, and the location of the lesion to be treated allows an appropriate choice of access for nonoperative procedures in the biliary system.