Background & Aims: Primary sclerosing cholangitis (PSC) is a chronic cholestatic liver disease characterized by inflammation and progressive bile duct fibrosis. There are limited data on pediatric PSC. Methods: we performed a retrospective chart review of 47 pediatric patients with PSC. Results: The mean age at diagnosis was 11 +/- 4.9 years. symptoms occurred before presentation in 81% of patients; inflammatory bowel disease was found in 59% and autoimmune hepatitis (overlap syndrome) in 25% of patients. Magnetic resonance cholangiography revealed both extrahepatic and intrahepatic, isolated intrahepatic, isolated extrahepatic, and no biliary involvement (small-duct PSC) in 40%, 14%, 10%, and 36%, respectively. Advanced fibrosis (stage >II) was present in 65%. Colonoscopy revealed pancolitis, rectal sparing, and normal findings in 24%, 24%, and 18%, respectively. All patients were treated with ursodeoxycholic acid (UDCA); 9 with overlap syndrome also received immunosuppressants. Fifteen patients without overlap syndrome had positive autoimmune markers and responded to UDCA monotherapy. Liver transplantation was performed in 9 patients (3 with overlap syndrome and 2 with small-duct PSC) at a median time of 7 years after diagnosis. The 10-year post-transplant survival rate was 89%. Conclusions; In one of the largest single-center studies of children with PSC, we found that most children with PSC had inflammatory bowel disease or autoimmune overlap and advanced fibrosis at diagnosis. Levels of atanine aminotransferase and,gamma-glutamyl transferase were highest in patients with overlap syndrome and lowest in those with small-duct PSC. Levels of serum liver enzymes normalized after therapy with UDCA, including patients with positive autoimmune markers without histologic features of autoimmune hepatitis.