Background: While a positive family history (FH) is a known risk factor for developing an aneurysm, its association with the extent of disease has not been established. We evaluated the influence of a FH of aortic disease with respect to the pattern and distribution of aortic aneurysms in a given patient. Methods and Results: From November 1999 to November 2011, 1263 patients were enrolled in physician-sponsored endovascular device trials to treat aortic aneurysms. Of the 555 patients who were alive and returning for follow-up, we obtained 426 (77%) family histories. Three-dimensional imaging studies were used to identify the presence of aneurysms; 36% (155/426) of patients had a FH of aortic aneurysms and 5% (21/155) had isolated intracranial aneurysms. A logistic regression model was used to compare aortic morphology between patients with a positive or negative FH for aneurysms. Patients with a positive FH of aortic aneurysms were younger at their initial aneurysm (63 vs 70 years; P <.0001), more frequently had proximal aortic involvement (root: odds ratio [OR], 5.4; P <.0001; ascending: OR, 2.9; P <.001; thoracic: OR, 2.2; P =.01) with over 50% of FH patients ultimately developing suprarenal aortic involvement (P =.0001) and had a greater incidence of bilateral iliac artery aneurysm (OR, 1.8; P =.03). Conclusions: FH is an important tool that provides insight into the expected behavior of the untreated aorta and has significant implications for the development of treatment strategies. These findings should be used to guide patient's management with regard to treatment, follow-up paradigms, genetic testing, and screening of other family members. Copyright © 2013 by the Society for Vascular Surgery.