Seventeen children with chronic active hepatitis and high serum titers of smooth-muscle or liver-kidney microsomal antibodies were given prednisone and azathioprine. Clinical and biochemical remission was obtained in all but two, who died of progressive liver failure. Evaluations in 14 children after a mean period of 22 months of treatment showed normal transaminase activity and gammaglobulin levels in 12, and serum autoantibody titers of less than 1: 100 in 10; liver histologic findings showed absence of inflammation in seven children, moderate portal or lobular inflammation in five, and minor features of aggressivity in two. Cessation of therapy was then attempted in nine children. Relapse occurred in all but one and could not be attributed to any previously recorded biologic or histologic feature. After follow-up of 18 months to 7 years, all but two patients are still receiving maintenance therapy with prednisone and azathioprine. Cirrhosis was present before treatment in 13 children and is now present in all but one. These results suggest that in most children with autoimmune chronic active hepatitis, immunosuppressive therapy can prevent further deterioration of liver function but must be pursued for several years before discontinuation is attempted.