Nontraumatic emergencies involving the abdominal vasculature are common and associated with significant morbidity and mortality. These conditions are almost always diagnosed or confirmed using cross-sectional imaging, and thus the radiologist plays an essential role in guiding appropriate patient management. Computed tomographic (CT) angiography is the workhorse modality for evaluating patients with suspected acute vascular pathology, but magnetic resonance angiography may be appropriate in carefully selected patients. Abdominal aortic aneurysms (AAA) are frequently encountered in practice; however, findings of aneurysm instability or rupture may be subtle but are critically important to identify. Following open AAA repair, complications may include anastomotic pseudoaneurysm, aortoenteric and aortopancreatic fistula, graft infection, and thrombosis. After endovascular AAA repair, important complications include endoleak, rupture, stent kinking, thrombosis, and infection. Aortitis and periaortitis can occur due to a broad variety of causes. Of these, infectious aortitis is most concerning, as it can progress rapidly to infectious pseudoaneurysm and rupture. Acute aortic occlusion, while uncommon, is associated with high morbidity and mortality. Acute pathology affecting the medium-sized abdominal vessels includes vasculitis, segmental arterial mediolysis (SAM), pseudoaneurysm, and embolic or thrombotic occlusion. Complications of medium-vessel pathology present acutely and commonly include hemorrhage and visceral ischemia. The objective of this chapter is to review and illustrate the most important nontraumatic abdominal vascular emergencies and their associated complications.