Purpose: To describe the technique of transvenous access for emergent endovascular repair of thoracic and thoracoabdominal aneurysms exemplified with 2 cases. Technique: Transvenous access to the aorta is described as an alternative access method to deliver aortic endografts in emergency situations. A 68-year-old female patient with severely compromised iliac and subclavian artery access was treated for a ruptured extent V thoraco-abdominal aortic aneurysm with a t-Branch (Cook Medical, Bjaeverskov, Denmark) delivered through a transcaval access. To avoid severe aortocaval shunting a balloon-expandable covered stent was deployed through a carotid access due to severe bilateral subclavian ostial stenosis. A 71-year-old man with an acute type B aortic dissection and bilateral narrow long-segment stenting of the iliac arteries was treated with a physician-modified thoracic endovascular aortic repair using an arteriovenous fenestration created at the level of the common iliac artery. We describe the access creation by fenestration using a transseptal needle. Conclusion: Transvenous access for thoracic and thoraco-abdominal aortic aneurysm repair is safe and feasible in selected emergent cases. Clinical Impact A transvenous approach may be helpful in selected patients when an endovascular repair needs to be performed but no arterial femoral access is available. This approach proved to be feasible even with large-bore introducer sheaths, taking its place in the armamentarium of the vascular surgeon for emergent complex endovascular aortic repairs.