Among prognostic factors of hilar cholangiocarcinoma, resectability and resection margin status can be modified by a surgeon. Therefore, complete resection without residual tumor is primary goal of surgical therapy for hilar cholangiocarcinoma. If we think of both vertical invasion and longitudinal infiltration mode of hilar cholangiocarcinoma, right trisectionectomy with caudate lobectomy may be best surgical option in terms of anatomical relationship of ductal bifurcation and vascular structure. According to the study from Nagoya University, longitudinal extension consists of predominant mucosal infiltration in papillary and nodular tumors or submucosal infiltration in sclerosing tumors. They reported a mean length of 10-20 mm for mucosal spread and 6-10 mm for submucosal spread. P Neuhaus from Berlin also insists that RTS is the most preferable approach from the oncological point of view aiming at wider margins. We also have reported our data in 2008. Although there were many complications, we could get cancer free proximal margin in all case and no in-hospital mortality, fortunately. Moreover, 64.4% of high 5 year survival rate was achieved. When we analyzed 203 cases who underwent right sided hepatectomy recently, R0 resection rate was higher in right trisectionectomy group than in right- or extended right hemihepatectomy group, and 5 year survival rate was 55.7% when combined caudate lobectomy was carried out with right trisectionectomy. In conclusion, right triectionectomy with caudate lobectomy may be procedure of choice for right sided hilar cholangiocarcinoma to achieve both higher R0 resection and survival rate. In my special lecture, I would like to show isolated caudate lobectomy and so called anatomical right trisectionectomy for hilar cholangiocarcinoma with video presentation.