BACKGROUND: A gender-neutral threshold aneurysm diameter (AD) of more than 5.5 cm for surgical intervention in abdominal aortic aneurysms (AAA) ignores the fact that women have a smaller baseline AD. We hypothesized that women have a greater AD relative to body surface area (BSA) at the time of surgery and that this worsens outcome. METHODS: The Vascular Study Group of New England database was queried for elective AAA repairs performed from 2003 to 2011 to compare BSA-indexed AD, ie, aortic size index (ASI), between men and women at the time of surgery and the impact of ASI on outcome. RESULTS: Women were older and had higher ASI among both open-repair (n = 1,566) and endovascular repair (n = 2,172) patients (P .001). Among open-repair patients, mean ASI for men undergoing repair at AD of 5.5 cm (2.75 cm/m²) was used to subdivide women into 2 categories: women with ASI of 2.75 or more were older (P .001), had a larger aneurysm size (P .001), and had a higher 1-year mortality (P = .042) than women with ASI less than 2.75. CONCLUSIONS: When indexed to BSA, women have a larger aneurysm size than men at the time of AAA repair.