Rationale: Use of triggers for palliative care consultation has been advocated in intensive care units (ICUs) to ensure appropriate specialist involvement for patients at high risk of unmet palliative care needs. The volume of patients meeting these triggers, and thus the potential workload for providers, is unknown. Objectives: To estimate the prevalence of ICU admissions who met criteria for palliative care consultation using different sets of triggers. Methods: Retrospective cohort study of ICU admissions from Project IMPACT for 2001β2008. We assessed the prevalence of ICU admissions meeting one or more primary palliative care triggers, and prevalence meeting any of multiple sets of triggers. Measurements and Main Results: Overall, 53,124 (13.8%) ICU admissions met one or more primary triggers for palliative care consultation. Variation in prevalence was minimal across different types of units (mean 13.3% in medical ICUs to 15.8% in trauma/burn ICUs; P = 0.41) and individual units (mean 13.8%, median 13.0%, interquartile range, 10.2β16.5%). A comprehensive model combining multiple sets of triggers identified a total of 75,923 (19.7%) ICU admissions requiring palliative care consultation; of them, 85.4% were captured by five triggers: (1) ICU admission after hospital stay greater than or equal to 10 days, (2) multisystem organ failure greater than or equal to three systems, (3) stage IV malignancy, (4) status post cardiac arrest, and (5) intracerebral hemorrhage requiring mechanical ventilation. Conclusions: Approximately one in seven ICU admissions met triggers for palliative care consultation using a single set of triggers, with an upper estimate of one in five patients using multiple sets of triggers; these estimates were consistent across different types of ICUs and individual units. These results may inform staffing requirements for providers to ensure delivery of specialized palliative care to ICU patients nationally