Introduction: Participants perceptions of their research experiences provide valuable measures of ethical treatment, yet no validated instruments exist to measure these experiences. We conducted focus groups of research participants and professionals as the initial step in developing a validated instrument. Methods: Research participants enrolled in 12 focus groups, consisting of: (1) individuals with disorders undergoing interventions; (2) in natural history studies; or (3) healthy volunteers. Research professionals participated in six separate groups of: (1) institutional review board members, ethicists, and Research Subject Advocates; (2) research nurses/coordinators; or (3) investigators. Focus groups used standard methodologies. Results: Eighty-five participants and 29 professionals enrolled at eight academic centers. Altruism and personal relevance of the research were commonly identified motivators; financial compensation was less commonly mentioned. Participants were satisfied with informed consent processes but disappointed if not provided test results, or study outcomes. Positive relationships with research teams were valued highly. Research professionals were concerned about risks, undue influence, and informed consent. Conclusions: Participants join studies for varied, complex reasons, notably altruism and personal relevance. They value staff relationships, health gains, new knowledge, and compensation, and expect professionalism and good organization. On the basis of these insights, we propose specific actions to enhance participant recruitment, retention, and satisfaction. Clin Trans Sci 2011; Volume 4: 403-413