To determine the clinical, biochemical, and histological features, and outcome of childhood autoimmune hepatitis (AIH), we reviewed the medical records of 52 children with AIH, 32 (median age: 10 [2-15] years) anti-nuclear and/or smooth muscle antibody (ANA/SMA) positive, 20 (7 [0.8-14] years) liver/kidney microsomal antibody (LKM-1) positive, with median follow-up of 5 years (range 0.3-19). At presentation: 56% had symptoms of prolonged acute hepatitis; LKM-1 positive were younger (P = .011), with higher bilirubin (P = .007), and AST (P = .047); ANA/SMA positive had lower albumin (P = .023); 69% ANA/SMA positive, and 38% LKM-1 positive were cirrhotic (P = .080). ANA/SMA positive had increased frequency of HLA haplotype A1/B8/DR3/DR52a compared with controls (53% vs. 14%, P < .001). Of six (5 LKM-1 positive) with fulminant hepatitis, four were transplanted, one died, and one ANA/SMA positive improved with immunosuppression. Of 47 treated with immunosuppression, 2 (1 LKM-1 positive) died with no remission and 4 (2 LKM-1 positive) were transplanted 8 to 14 years after diagnosis. Immunosuppression was stopped successfully in 19% of ANA/SMA positive after a median of 3 years of treatment, but in none of LKM-1 positive. Baseline bilirubin and international normalized prothrombin ratio (INR) were independent variables predictive of outcome. In conclusion, ANA/SMA positive and LKM-1 positive AIH in childhood have clinical, biochemical, and histological differences, but similar severity and long-term outcome.