Primary biliary cirrhosis (PBC) is an uncommon chronic cholestatic liver disease that primarily afflicts young and middle-aged Caucasian women; there are limited data on the clinical presentation and disease severity among non-Caucasian patients with this disease. The goal of this study was to examine differences in the severity of liver disease between Caucasian and non-Caucasian patients with PBC screened for enrollment in a large national multicenter clinical trial. Demographic features, symptoms, physical findings, and laboratory tests obtained during screening were examined in 535 patients with PBC with respect to ethnicity, gender, and antimitochondrial antibody (AMA) status; 73 of 535 (13.6%) were non-Caucasian (21 were African American, and 42 were Hispanic). Non-Caucasians were more likely than Caucasians to be ineligible for participation in the clinical trial (46.5% versus 25.1%, P = 0.0001), primarily because of greater disease severity. African Americans and Hispanics were also more likely to have a lower activity level, more severe pruritus, and more advanced disease. However, the mean age, male-to-female ratio, and seroprevalence of AMA positivity were similar between the 2 groups. Conclusion: Liver disease severity at clinical presentation is higher among non-Caucasians than Caucasians with PBC, and this cannot be explained by demographic or serologic features alone. Possible mechanisms underlying this health discrepancy are not clear, but increased awareness of PBC as a cause of chronic cholestatic liver disease is critical in evaluating non-Caucasian patients in the United States. (HEPATOLOGY 2007.)