Primary sclerosing cholangitis (PSC) is a rare but important liver disease that leads to cirrhosis and need for liver transplantation in a high proportion of cases. The disease occurs in approximately 1 per 100,000 population per year, usually presents in adulthood, and affects men more often than women. Typical serum biochemical results, autoantibodies and liver biopsy are suggestive but not diagnostic of PSC, the diagnosis requires cholangiographic demonstration of stricturing and dilatation of the intra- and/or extra-hepatic bile ducts. As a result of the unknown cause of the disease, current medical therapies are unsatisfactory. The most dreaded complication of PSC is cholangiocarcinoma (CC); the diagnosis and treatment of this malignancy still remains a challenge in PSC patients. Early diagnosis of CC certainly is a prerequisite for successful treatment. Endoscopic techniques such as cholangioscopy and/or intraductal ultrasound may be useful diagnostic tools in patients with stenoses suspicious for malignancy. In this lecture, indications, benefits and limits of these techniques are shown through a 5-year experience in 53 patients.