Klatskin tumors are defined as malignant tumors of the bile duct involving the bifurcation and intrahepatic bile ducts. The most common presenting clinical feature, obstructive jaundice, usually occurs with advanced disease. Diagnostic tools currently available are therefore either performed too late or are not able to detect early disease stage. Imaging procedures for diagnosis and staging are ultrasonography, magnetic resonance imaging with cholangiopancreaticography, intravenous bolus-enhanced spiral computed tomography and endoscopic retrograde cholangiopancreaticography. Before initiating any palliative measure, a proper staging and a surgical consultation at a hepatobiliary center is necessary. To assess resectability, additional diagnostic methods like angiography, positron emission tomography, cholangioscopy, endoscopic or intraluminal ultrasonography and finally even explorative laparoscopy may be required. At time of diagnosis only a small percentage of Klatskin tumors is curative resectable. Therefore, palliative treatment options play an important role. Endoprostheses insertion is the method of choice to relieve jaundice. Although it improves quality of life, it does not seem to improve survival time. Definitive evidence for a benefit of additional radio and/or chemotherapy is still missing. Photodynamic therapy, a light therapy, is the first approach leading to an improvement of cholestasis and quality of life as well as to a prolongation of survival time. PDT should therefore be offered to all patients with nonresectable cholangiocarcinoma.