Cholangiocarcinoma is the primary malignancy arising from the biliary epithelium, and it presents as jaundice, cholestasis, and cholangitis. Over 50 percent of patients present with advanced-stage disease, and the prognosis is poor with the survival measured in months even after biliary decompression. Palliative management has become the standard of care for unresectable disease, and this involves an endoscopic approach. Photodynamic therapy (PDT) involves the administration of a photosensitizer followed by local irradiation with laser therapy. The use of PDT for palliation of bile-duct tumors has produced promising results. Several studies conducted in Europe and the United States have shown that PDT produces a marked improvement in the symptoms of cholestasis, survival, and quality of life. This chapter summarizes the principle of PDT, the technique employed, and the published experience regarding PDT for cholangiocarcinoma.