Hypothesis: "Opinion leaders" can be identified by surgeons from among their peers, and opinion leaders have a role in promoting best surgical practice.Design: Postal survey.Setting and Participants: Four hundred eighteen (77% response fraction) randomly selected fellows of the Royal Australasian College of Surgeons.Main Outcome Measures: Number of opinion leaders identified locally, statewide, and nationally; ratings of 22 possible attributes in conferring status as an opinion leader; and views about and ratings of the role of opinion leaders.Results: Most respondents were unable to identify a local colleague whom they considered to be an opinion leader in their own specialty (mode, 0; and median, 1) or in surgery in general (mode, 0; and median, 0). Estimated numbers of opinion leaders were significantly higher at the state and national levels for the respondents' own specialty and for surgery in general (P<.001 for all). Surgical expertise and teaching skills were rated most highly as conferring status as an opinion leader. Academic and professional contributions received the lowest ratings. Most surgeons (88%; 95% confidence interval, 84%-91%) agreed that opinion leaders could influence them to change their practice. Opinion leaders were rated as "very influential" by significantly more surgeons than clinical audit (38% vs; 27%, chi(1)(2) = 13.6, P<.001) and clinical cal practice guidelines (38% vs 24%, chi(1)(2)=21.4,P<.001) (McNemar test for both).Conclusions: Australian surgeons support the concept of opinion leaders. Although few local colleagues whom they consider as fulfilling such a role can be identified, opinion leaders are evident at a national level. Once opinion leaders are identified using attributes ranked in our survey, interventional studies will further delineate their influence in improving evidence-based surgical practice.