OBJECTIVE To examine the knowledge of, previous experience with, attitudes toward and perceived barriers to completing advance directives among outpatients at two general medicine clinics. METHODS Cross-sectional questionnaire administered in face-to-face structured interviews. METHODS General internal-medicine outpatient clinics at a university teaching hospital. METHODS One hundred and five adult outpatients who could communicate in spoken English and who consented to be interviewed. RESULTS Of 167 patients approached, 58 were excluded because they could not communicate in spoken English, and 4 refused to participate. Of the remaining 105 patients, 17 (16%) knew about living wills, 12 (11%) about durable powers of attorney for health care and 4 (4%) about advance directives. Twenty-three (22%) had thought about their preferences for life-sustaining treatment, 20 (19%) had discussed them, none had written them down, and 45 (43%) had thought about choosing a proxy. Sixty-one (58%) wanted to think about their preferences for treatment, 65 (62%) wanted to discuss them, 32 (30%) wanted to write them down, and 80 (76%) wanted to choose a proxy. The perceived barriers to completing an advance directive were inability to write, the belief that an advance directive was unnecessary, a fatalistic attitude, previous discussion of preferences, a desire to leave the decision to doctors, uncertainty about preferences, a desire to discuss preferences rather than document them, a desire to wait until the situation arose, a desire to write down preferences in the future and a desire to avoid thinking about preferences or advance directives. Respondents with more knowledge of life-sustaining treatments were more likely to want to complete an advance directive. CONCLUSIONS Outpatients have positive attitudes toward advance directives, but their knowledge and experience are limited. These data underscore the need for patient education and for policies to eliminate the barriers to completing advance directives that patients face.