Late graft dysfunction (GD) associated with the development of autoantibodies is a common event after pediatric liver transplantation (OLTx) and can present in 2 clinicohistological subsets: de novo autoimmune hepatitis (DNAH) and early chronic rejection (ECR). Sixty out of 247 children developed autoantibodies after OLTx. GD was demonstrated in 22 (37%); based on histology, patients were divided in a DNAH and an ECR group. Portal/periportal inflammatory infiltrate with interface/lobular hepatitis was suggestive for DNAH. Pericentral hepatocytes confluent dropout with a variable degree of central vein endothelitis, but not with ductopenia (loss of >50% of interlobular bile ducts), was diagnosed as ECR. Nine patients had DNAH and 13 ECR. Five out of 9 in the DNAH group were on cyclosporin (CsA) and 4/9 were on tacrolimus (Tac). In the ECR group, 11 children were treated with CsA and 2 with Tac. All DNAH patients had normal liver function tests on steroids and azathioprine (AZA). Five patients with ECR recovered by increasing calcineurin inhibitors (CNIs) dosage, but in 8/13, including 7 switched from CsA to Tac, AZA and steroids were added to obtain remission of disease. Two patients developed late chronic rejection. DNAH and ECR associated with autoantibodies are forms of late GD after OLTx. DNAH improves after standard treatment of autoimmune hepatitis. ECR has a good response to increased doses of CNIs, although ductopenic chronic rejection may occur. In conclusion, the early differential diagnosis of these conditions and an appropriate treatment seem to allow good overall results reflected by a graft survival of more than 90%. Liver Transpl 12:573–577, 2006. © 2006 AASLD.