Recently we have been performing S4a + S5 with total resection of the caudate lobe (S1) by using a dome-like dissection along the root of the middle hepatic vein at the pinnacle, which we refer to as the Taj Mahal liver parenchymal resection, for carcinoma of the biliary tract. This procedure offers the following advantages: (1) It allows total resection of the caudate lobe, including the paracaval portion (S9), and (2) because the cut surface of the liver is large, it allows intrahepatic jejunostomy to be performed more easily with a good field of view. The indications for this procedure include hilar bile duct carcinoma, gallbladder carcinoma, and choledochal cyst (type IVA). Because of the high rate of hilar liver parenchyma and caudate lobe invasion associated with hilar bile duct carcinoma, the liver must be resected. The Taj Mahal procedure is indicated in cases where extended liver resection is impossible. The dissection limits of this procedure are, on the left side, the B2+3 bifurcation at the right margin of the umbilical portion of the portal vein and, on the right side, the B8 of the anterior branch and the B6+7 bifurcation of the right posterior branch. This procedure could also be described as a reduced form of extended right hepatectomy and extended left hepatectomy. For gallbladder carcinoma, this procedure is indicated to ensure an adequate surgical margin and eradicate transvenous liver metastasis, particularly in cases of pT2 lesions. Hilar and caudate lobe invasion also occurs in liver bed-type gallbladder carcinoma, and bile duct resection and caudate lobe resection are required for the surgery to be curative. We performed this procedure in four cases of hilar bile duct carcinoma, five cases of gallbladder carcinoma, and one case each of choledochal cyst (type IVA) with carcinoma of the bile duct and gallbladder adenomyomatosis. Curative resection was possible in all except the patient with adenomyomatosis, and all of the patients are alive and recurrence free 10 to 37 months postoperatively. This procedure, in addition to preserving liver function, provides a wide field of view and facilitates reconstruction of multiple intrahepatic bile ducts. Thus it can be said to be a curative operation not only in patients considered high risk but also in those whose hilar bile duct carcinoma is limited to the bifurcation area (Bismuth type IIIa and IIIb) and in gallbladder carcinoma up to pT2 with slight extension on the hepatic side.