On November 30, a workshop of IRDiRC’s Task Force on Patient-Centered Outcome Measures (PCOM) took place in Paris, France. The purpose was to identify what should and can be done to support the development of patient-relevant outcome measures for rare diseases, in order to improve the feasibility and quality of forthcoming trials and to provide data of relevance to the patient community and other decision makers. The workshop focused on what is transferable to rare diseases of the experience gained so far with common diseases. The discussions in the morning addressed three aspects of the issue: how to develop PCOM, how to find existing tools to be adopted or adapted, and how to evaluate and expand on those tools. Several real-life examples with in different clinical trials were given; how well set-out PCOMs have contributed to successful clinical trials or the reverse. The next session was dedicated to ways to help and support the rare disease community, including ways how to raise awareness about PCOM; the development of training tools; the different databases of outcome measures. The last session centered on the development of PCOM for RD; ways to share expertise; organization and funding of the development and guidelines for the development. The workshop ended with the identification of next steps and decisions on how to report on the workshop outcome.