Objectives: The literature on participation in priority-setting has three key gaps: it focuses on techniques for obtaining public input into priority-setting that are consultative mechanisms and do not involve the public directly in decision-making; it focuses primarily on the public's role in priority-setting, not on all potential participants; and the range of roles that various participants play in a group making priority decisions has not been described. To begin addressing these gaps, we interviewed individuals who participated on two priority-setting committees to identify key insights from participants about participation. Methods: A qualitative study consisting of interviews with decision-makers, including patients and members of the public. Results: Members of the public can contribute directly to important aspects of priority-setting. The participants described six specific priority-setting roles: committee chair, administrator, medical specialist, medical generalist, public representative and patient representative. They also described the contributions of each role to priority-setting. Conclusions: Using the insights from decision-makers, we have described lessons related to direct involvement of members of the public and patients in priority-setting, and have identified six roles and the contributions of each role.