Objective. Since 2002, 58 patients have participated as collaborating partners in 6 Outcome Measures in Rheumatology (OMERACT) conferences. Little is known about how they engage with researchers and how they have influenced conference outcomes. Methods. A responsive evaluation was carried out, including a thematic document analysis of conference proceedings and gray literature, participant observation, and 38 interviews with patients and professionals representing research, industry, and regulators. Interview transcripts were subjected to an inductive content analysis. Results. The role of patients has evolved from a single focus group in 2002 to full integration in all parts of the conference in 2012. Longterm engagement has made a significant change in the scope and conduct of rheumatology research. It has enriched the research agenda by identifying previously neglected outcome domains such as fatigue, sleep disturbances, and flares, and it has contributed to more patient-relevant outcomes in clinical trials. Facilitating factors have been a strong commitment of the leadership, adequate selection procedure, inclusive conference design, interactive and encouraging moderation style, and self-organized support. The intensity of the program and doubts regarding the representativeness of the patient group were still seen as challenges for the future. Conclusion. Making patient participation an integral part of the vision and procedures of OMERACT has significantly contributed to the success of OMERACT. It has changed the perceptions and beliefs of many participants. Full use of patients' experiential knowledge before and during the conference is still challenging.