: We sought to characterize the incidence, nature, and course of liver disease in children with inflammatory bowel disease (IBD). Chart review identified 555 subjects (318 Crohn's disease [CD], 237 ulcerative colitis [UC]). An alanine aminotransferase measurement of โฅ80 U/L was used to identify the presence of a hepatic abnormality. Seventy-five patients (47 CD, 28 UC) had at least one ALT level โฅ80 U/L. Persistent ALT elevation (>6 months) was found in 14 patients: 10 with sclerosing cholangitis (SC) (eight UC, two CD) and four with autoimmune chronic active hepatitis (CAH) (one UC, three CD). One patient with SC has had hepatic transplantation, and one other has end-stage liver disease. The remainder are clinically well. Two patients with CAH have developed cirrhosis. Nonpersisting ALT elevations (<250 U/L) were noted during disease course in 61 patients and were associated with medications, parenteral nutrition, bowel obstruction, and flare-ups of disease. Most ALT elevations in children with IBD are transient and appear to relate to medications or disease activity. Sclerosing cholangitis was noted in 3.5% of UC patients and <1% of CD patients, while CAH was found in <1% of UC or CD patients. Unless evidence of chronic liver disease is present, the initial finding of mild to moderate ALT elevation (80-250 U/L) should prompt observation before extensive evaluation.