Abdominal aortic aneurysms (AAAs) comprise the tenth leading cause of death in Caucasian males 65 to 74 years of age and accounted for nearly 16,000 deaths overall in 2000. Therefore, understanding the pathophysiology of AAAs is an important undertaking. Clinically, multiple risk factors are associated with the development of AAAs, including increasing age, positive smoking history, and hypertension. Male gender is also a well-established risk factor for the development of an AAA, with a 4:1 male to female ratio. The reason for this gender disparity is unknown. The pathogenesis of AAAs formation is complex and multifactorial. Histologically, AAAs are characterized by early chemokine-driven leukocyte infiltration into the aortic wall. Subsequent destruction of elastin and collagen in the media and adventitia ensues owing to excessive local production of matrix-degrading enzymes and is accompanied by smooth muscle cell loss and thinning of the aortic wall. At present, no medical therapies are available to treat patients with aortic aneurysms, using only the crude measurement of aortic diameter as a threshold for which patients must undergo life-threatening and costly surgery. Defining the early mechanisms underlying gender-related differences in AAA formation is critical as understanding differences in disease patterns based on gender may allow us to develop new translational approaches to the prevention and treatment of patients with aortic aneurysms.