Patients with primary biliary cirrhosis (PBC) may have additional features of autoimmune hepatitis (AIH). Corticosteroids usually contraindicated in PBC have been advocated for these patients. Patients with antimitochondrial antibody (AMA)-positive PBC from two previous randomized, controlled trials were assessed for features of AIH. Their biochemical, immunologic, and histologic responses to ursodeoxycholic acid (UDCA) versus placebo were compared with those without AIH features. The survival of patients testing positive or negative for antinuclear antibodies (ANA) was also examined. Features of AIH were defined by the presence of 2 or more of the following: 1) alanine transaminase (ALT) > 5× the upper limit of normal (ULN); 2) immunoglobulin G (IgG) > 2× ULN or positive anti-smooth muscle antibody (ASMA); and 3) moderate to severe lobular inflammation on pretreatment liver biopsy. Testing for AMA, ASMA, and ANA was done by immunofluorescence. The change in serum bilirubin, alkaline phosphatase (ALP), transaminases, IgM, and IgG from baseline to 2 years was compared. Of the 331 patients randomized, 16 (4.8%) had features of AIH (12 UDCA, 4 placebo). The median percent change in serum biochemistry and immunoglobulin values were similar in patients with PBC ± features of AIH after 2 years of therapy with UDCA. Over 2 years, little change in histologic features of AIH was observed. Survival was similar for patients with PBC with and without ANA. In conclusion, features of AIH in PBC may be transient and response to UDCA therapy similar to patients with PBC without features of AIH.