The Pediatric Intensive Care Unit (PICU) Core Outcome Set (COS) is an international, multi-stakeholder and evidence-informed COS for clinical and research use in pediatric critical illness.  Core outcome sets are defined as “a patient outcome, health‐related condition, or aspects of health that relevant stakeholders agree are essential to assess in all clinical research studies evaluating outcomes.” The PICU COS serves as a guide to assure that outcomes most important to all stakeholders are considered in PICU clinical research or clinical care programs.