BACKGROUND To determine the relative impact of five proposed barriers to physician usage of advance directives with the aim of increasing the number of advance directives generated. METHODS Questionnaires were sent to 460 internal medicine resident and attending physicians at a large New York, NY, hospital. Of these, 277 (60%) responded. We used multiple regression to measure the impact of five barriers to physician-initiated discussions of advance directives (time constraints, compensation concerns, discomfort with the subject, beliefs about appropriateness, and lack of understanding) on respondents' estimates of the number of advance directives held by respondents' patients, the number of recent advance directive discussions, and the number of discussions initiated by physicians. RESULTS Physician lack of understanding and erroneous beliefs about appropriateness had particularly strong effects, serving as barriers to recent advance directive discussions (P < .0001 and P < .0001, respectively) and total number of advance directives held (P < .0001 and P < .02). Physicians' lack of knowledge also served as a barrier to the percentage of discussions that were physician initiated (P < .003 and P < .04). Time constraints and lack of comfort affected only discussions that were physician initiated (P < .001). Compensation concerns did not appear to serve as a barrier. Respondents were supportive of the concept of advance directives but reported minimal use of them in appropriate situations. CONCLUSIONS Attention can now be focused on methods to overcome the five barriers studied and thereby enhance the execution of advance directives.