Liver transplantation (LT) is the only therapeutic option for end-stage primary sclerosing cholangitis (PSC), but PSC can recur (rPSC) in some patients after LT. The aim of our study was to evaluate the risk factors associated with rPSC. Between 1989 and 2004, 69 patients receiving transplantation for PSC (42 male, mean age 41.9 yr). Clinical and laboratory data, activity/extension and treatment of ulcerative colitis (UC), post-LT cytomegalovirus (CMV) infection, and immunosuppression were evaluated. Determination of rPSC was made by radiological and histological findings. Exclusion criteria were ABO blood group incompatibility, hepatic artery stenosis, and biliary strictures occurring in <3 months post-LT. A total of 48 (70%) patients had PSC and UC pre-LT. rPSC occurred in 7 of 53 (13.5%, 2 patients with de novo UC) who were alive 1 yr after LT and/or met inclusion/exclusion criteria: median 60 (4-120) months. No patient without post-LT UC had rPSC: 0 of 20 vs. 7 of 26 with post-LT UC (P = 0.027). The multivariate logistic regression analysis showed that maintenance steroids for UC (>3 months) post-LT was the only risk factor significantly associated with rPSC (P = 0.025). In conclusion, the presence of UC post-LT, and the need for maintenance steroids post-LT, which is an independent factor, are associated with rPSC. These findings could help elucidate a possible mechanism of PSC pathogenesis.