Over a 15-yr period of observation, among the 205 children who underwent liver transplantations, one of them developed a particular type of late graft dysfunction with clinical and histological similarity to autoimmune hepatitis. The patient had alpha1-antitrypsin deficiency and did not previously have autoimmune hepatitis or any other autoimmune disease before transplantation. Infectious and surgical complications were excluded. After repeated episodes of unexplained fluctuations of liver function tests and liver biopsies demonstrating reactive or a biliary pattern, without any corresponding alteration of percutaneous cholangiography, a liver-biopsy sample taken 4 yr after the transplant showed active chronic hepatitis progressing to cirrhosis, portal lymphocyte aggregates, and a large number of plasma cells. At that time, autoantibodies (gastric parietal cell antibody, liver-kidney microsomal antibody, and anti-hepatic cytosol) were positive and serum IgG levels were high. Based on these findings of autoimmune disease, a diagnosis of 'de novo autoimmune hepatitis' was made. The treatment consisted of reducing the dose of cyclosporine, reintroduction of corticosteroids, and addition of mycophenolate mofetil. After 19 months of treatment, a new liver-biopsy sample showed marked reduction of portal and lobular inflammatory infiltrate, with regression of fibrosis and of the architectural disruption. At that time, serum autoantibodies became negative. The last liver-biopsy sample showed inactive cirrhosis and disappearance of interface hepatitis and of plasma cell infiltrate. Presently, 9 yr after the transplantation, the patient is doing well, with normal liver function tests and no evidence of cirrhosis. Her immunosuppressive therapy consists of tacrolimus, mycophenolate mofetil, and prednisolone. In conclusion, the present case demonstrates that de novo autoimmune hepatitis can appear in liver-transplant patients despite appropriate anti-rejection immunosuppression, and triple therapy with tacrolimus, mycophenolate mofetil, and prednisolone could sustain the graft and prevent retransplantation.