To determine the frequency and nature of variant syndromes in autoimmune liver disease, 162 patients with type 1 autoimmune hepatitis, 37 patients with primary biliary cirrhosis, and 26 patients with primary sclerosing cholangitis were assessed in a uniform fashion, and the strength of the original diagnosis was evaluated by use of a scoring system. Variant forms, including syndromes with autoimmune hepatitis and primary biliary cirrhosis (7%) or primary sclerosing cholangitis (6%) and autoimmune cholangitis (11%), were common in the 225 patients (18%). Individuals with autoimmune hepatitis and primary biliary cirrhosis entered remission during corticosteroid therapy as commonly as individuals with definite autoimmune hepatitis (75% vs. 64%, P = .5), and they responded better than patients with autoimmune hepatitis and primary sclerosing cholangitis (75% vs. 22%, P = .03) or autoimmune cholangitis (75% vs. 0%, P = .009). Patients with autoimmune hepatitis and primary sclerosing cholangitis had a higher frequency of a poor result than other variants (78% vs. 17%, P = .04), and they died of liver failure or required liver transplantation more often than patients with definite autoimmune hepatitis (33% vs. 8%, P = .05). None of the patients entering remission had serum alkaline phosphatase levels greater than twofold the reference value. In conclusion, variants of autoimmune liver disease are common. Corticosteroid therapy can be effective in patients with features of autoimmune hepatitis and primary biliary cirrhosis. A serum alkaline phosphatase level of less than twofold the reference value characterizes corticosteroid-responsive individuals.