Orthotopic liver transplantation (OLT) has become the only effective therapeutic option for patients with end-stage liver disease caused by primary sclerosing cholangitis (PSC). Excellent long-term outcome has been reported, with 5-year patient survival rates of approximately 80%. In the last few years, increasing evidence has emerged that PSC recurs after OLT. The diagnosis of PSC is based on well-defined cholangiographic features combined with biochemical and histological findings. However, none of these features is specific for PSC, particularly after OLT, because biliary strictures in the liver allograft can occur from a variety of causes other than recurrence. Therefore, PSC recurrence remains a controversial issue, especially because of a lack of a gold standard for diagnosis and well-established diagnostic criteria. Some reports provided cholangiographic evidence that post-OLT biliary strictures occurred more frequently in patients with PSC than in those who underwent OLT for other liver diseases (including patients with a Roux-en-Y biliary reconstruction). Because no other possible cause of biliary strictures could be invoked to explain the greater prevalence of these strictures, recurrent disease has been implicated. There also is histological evidence suggesting that PSC recurs after OLT. Histological findings suggestive of PSC were found more often in PSC allografts compared with a control group. Furthermore, histological features typical for PSC (fibro-obliterative lesions) were seen exclusively in liver biopsy specimens from patients with PSC. Recurrence of PSC was defined in a recent study from the Mayo Clinic by means of strict cholangiographic and histological criteria in a large cohort of patients with PSC in whom other causes of biliary strictures were excluded. PSC recurrence was found in 20% of patients. No risk factor for PSC recurrence could be found, and recurrent disease did not influence patient or graft survival after a mean follow-up of 4.5 years. In conclusion, several studies provided convincing evidence that PSC recurs after OLT, with an incidence of 5% to 20% and an interval to diagnosis of at least 1 year after OLT. To date, patient and graft survival do not appear to be negatively affected by disease recurrence in the intermediate term of follow-up.