Patients usually receive a diagnosis of primary biliary cholangitis (PBC) at an early stage, based on biochemical analyses. We investigated the proportion of patients who progress to moderate or advanced PBC and factors associated with progression and patient survival. We obtained data from 1615 patients (mean age, 55.4 y) with early stage PBC (based on their normal levels of albumin and bilirubin), collected at the time of initial evaluation or treatment, from the Global PBC Study Group database (comprising patients at 19 liver centers in North American and European countries). We collected data from health care evaluations on progression to moderate PBC (abnormal level of bilirubin or albumin) or advanced-stage PBC (abnormal level of both). The median follow-up time was 7.9 years. The composite end point was decompensation, hepatocellular carcinoma, liver transplantation, or death. Of the 1615 patients identified with early stage PBC, 904 developed moderate PBC and 201 developed advanced disease over the study period. The proportions of patients who transitioned to moderate PBC at 1, 3, and 5 years were 12.9%, 30.2%, and 45.8%. The proportions of these patients who then transitioned to advanced PBC at 1, 3, and 5 years later were 3.4%, 12.5%, and 16.0%, respectively. During the follow-up period, 236 patients had a clinical event. The proportions of patients with moderate PBC and event-free survival were 97.9%, 95.1%, and 91.5% at 1, 3, and 5 years, respectively, and the proportions of patients with advanced PBC and event-free survival were 90.6%, 71.2%, and 58.3% at 1, 3, and 5 years later, respectively. Variables associated with transition from early to moderate PBC included baseline levels of bilirubin, albumin, and alkaline phosphatase; aspartate to alanine aminotransferase ratio; platelet count; and treatment with ursodeoxycholic acid. Transitions from early to moderate PBC and from moderate to advanced PBC were associated with higher probabilities of a clinical event (time-dependent hazard ratios, 3.0; 95% CI, 2.0-4.5; and 4.6; 95% CI, 3.5-6.2). Approximately half of patients with early stage PBC progress to a more severe stage within 5 years. Progression is associated with an increased risk of a clinical event, so surveillance is important for patients with early stage PBC. Copyright © 2020 AGA Institute. Published by Elsevier Inc. All rights reserved.