The diameter of an abdominal aortic aneurysm (AAA) is the single most important factor in deciding whether to repair an aneurysm or to monitor it conservatively. Open surgical repair does not appear to be beneficial until the diameter of the aneurysm is >5.5 cm. Prospective clinical trials, however, confirmed a lower risk of operative mortality after endovascular aneurysm repair (EVAR) than after open surgical repair. Further, retrospective analyses of EVAR databases suggested that EVAR outcome is directly related to aneurysm size and is better for smaller aneurysms than for larger aneurysms. Noting similar results with open surgical management vs surveillance in patients with smaller AAA, lower morbidity rates with EVAR vs open repair, and the favorable results with EVAR in smaller aneurysms, a clinical trial testing the hypothesis that EVAR is beneficial in patients with small AAA appeared warranted. To answer this question, the 70-site Positive Impact of endoVascular Options for Treating Aneurysm earLy (PIVOTAL) was begun. PIVOTAL has an enrollment goal of up to 1025 patients with a 4- to 5-cm AAA, randomly assigning patients to EVAR or surveillance. The primary end points of PIVOTAL are aneurysm rupture and AAA-related death at up to 36 months after randomization. When complete, the results of PIVOTAL should provide objective evidence to guide the use of EVAR for small AAAs.