Idiopathic pulmonary fibrosis (IPF) is a rare disease that is more common in older people. It causes scarring and swelling of the lungs. IPF continues to get worse and cannot be cured yet. Major progress has been made in diagnosing and treating IPF early on. Patient advocacy groups and lung specialists stress that patients living with IPF continue to have major unmet needs. Clinical IPF teams should offer patients a personalized treatment plan tailored to their individual needs. We still do not know exactly what outcomes (factors) are most important to patients and clinicians. Outcomes can cover whether a patient feels better or whether certain test results change following a treatment. Not knowing which outcomes are important can slow-down attempts to improve the care and quality of life of people living with IPF. The “Co-designing a Core Outcome Set for and with patients with Idiopathic Pulmonary Fibrosis” (COCOS-IPF) project aims to develop a Core Outcome Set and their corresponding measures for IPF care in Europe. A Core Outcome Set is a group of outcomes that have been agreed to be important and can be used by clinicians and researchers all over the world to support shared decision-making and to develop best practice models of care. We will involve patients or their representatives, family members, clinicians and policy makers from different countries and healthcare systems across Europe to determine what the core outcomes should be. This will ensure that we create a set of outcomes that patients and clinicians value the most within IPF care.