A core outcome set (COS) is an agreed standardised set of outcomes that should be measured and reported, as a minimum, in all clinical trials in a specific condition. This allows research to be compared and combined as appropriate, and ensures that all studies provide usable information. An increasing number of COS developers also intend their COS for use in routine clinical practice and real world evidence studies. Many public and private organisations now actively endorse the use of COS and the COMET database (http://www.comet-initiative.org/cosuptake), including the European Medicines Agency (http://www.comet-initiative.org/assets/downloads/Hans-Georg%20Eichler_COMET.mp4), NICE (https://www.nice.org.uk/process/pmg20/chapter/developing-review-questions-and-planning-the-evidence-review) and EFPIA (https://www.efpia.eu/media/412316/the-case-for-outcomes-document-17102018.pdf, section 10). Growing support from the pharmaceutical industry is demonstrated in the large number of companies involved in the IMI2 BD4BO project (http://bd4bo.eu/index.php/about-the-programme/partners/), a public-private partnership to ‘support the evolution towards patient-centred, outcomes-focused sustainable healthcare systems in Europe’. It is important that relevant stakeholders are involved in the development of COS to ensure that COS appropriately reflect outcomes that are important to those groups, particularly patients, healthcare professionals and those that will use the COS. There is a current interest in identifying how COS might fit into the different stages of the healthcare research system. With their proximity to reimbursement/coverage decisions, HTA bodies can increase awareness of COS, encourage COS development and support uptake of COS. Relevant bodies have identified the potential challenge of different bodies’ requirements for condition-specific versus generic quality of life outcomes in COS. These bodies are coming together to see how they can support COS in the healthcare research system.