Primary sclerosing cholangitis (PSC) is rare in the pediatric population. Little information exists on the progression of the disease in children. This study evaluated the experience with PSC at the Children's Hospital of Philadelphia over the past 20 years, with an emphasis on the histologic features at presentation, during disease progression, and after liver transplantation. We retrospectively reviewed the medical records of patients diagnosed with PSC between 1981 and 2001. Nineteen patients met the inclusion criteria with classic radiographic evidence of PSC. One additional patient with normal biliary imaging was subsequently diagnosed at the time of liver transplantation. The 20 patients with PSC (14 males) ranged in age from 1 month to 15 years at time of presentation. Inflammatory bowel disease was evident in 50% of patients. Initial histology revealed advanced disease (bridging fibrosis or cirrhosis) in 13 patients and an earlier histologic stage in 7 patients. Of the latter, 3 remain stable, 2 required transplantation, and 2 were lost to follow-up. Seven of the 13 patients with advanced disease required orthotopic liver transplantation, and 3 of these subsequently showed recurrence of primary disease in the allograft. Thus, most subjects presented insidiously at an advanced stage that required transplantation. Subjects who presented at an earlier stage progressed or remained stable, but the histologic findings at diagnosis were generally not predictive of disease progression. Recurrence of PSC after transplantation is a significant complication in children.