OBJECTIVE: Patient education is a fundamental responsibility of medical providers caring for patients with abdominal aortic aneurysms (AAA). We sought to evaluate and quantify AAA-specific knowledge in patients under AAA surveillance and in patients who have undergone AAA repair. METHODS: In 2013, 1373 patients from 6 U.S. institutions were mailed an AAA-specific quality of life and knowledge survey. Of these patients, 1008 (73%) returned completed surveys for analysis. The knowledge domain of the survey consisted of nine questions. An AAA knowledge score was calculated for each patient based on the proportion of questions answered correctly. The score was then compared according to sex, race, and education level. Surveillance and repaired patients were also compared. RESULTS: Among 1008 survey respondents, 351 were under AAA surveillance and 657 had AAA repair (endovascular repair, 414; open, 179; unknown, 64). The majority of patients (85%) reported that their "doctor's office" was their most important source of AAA information. The "Internet" and "other written materials" were each reported as the most important source of information 5% of the time with "other patients" reported 2% of the time. The mean AAA knowledge score was 47% (range 0%-100%; standard deviation, 23%) with a broad variation in percentage correct between questions. Thirty-two percent of respondents did not know that larger AAA size increases rupture risk, and 64% did not know that AAA runs in families. Only 15% of patients answered six or more of the nine questions correctly, and 23% of patients answered two or fewer questions correctly. AAA knowledge was significantly greater in men compared with women, whites compared with nonwhites, high school graduates compared with nongraduates, and surveillance compared with repaired patients. CONCLUSIONS: In a national survey of AAA-specific knowledge, patients demonstrated poor understanding of their condition. This may contribute to anxiety and uninformed decision making. The need for increased focus on education by vascular providers is a substantial unmet need.