OBJECTIVE This study reports the initial clinical results and experience with the planning of branched stent grafts in high-risk patients with thoracoabdominal aortic aneurysms (TAAAs). METHODS High-risk patients with TAAAs were considered for this study. Based on evaluation with computed tomography angiography (CTA), 21 custom-made branched stent grafts were designed for the selected patients. Two patients had associated bilateral aneurysms of the common iliac arteries, so an iliac branched device was also used. RESULTS Between August 2006 and April 2008, 23 patients (10 women, 13 men) were selected to undergo endovascular TAAA repair. Mean age was 72 years old. Two patients were excluded after 1-mm-slice CTA analysis. Eleven patients have underdone TAAA repair so far. The mean follow-up period at present is 8 months (range, 18 days-21 months). Overall technical success was accomplished in all 11 patients. Two renal artery branches occluded. Operative times varied from 3 to 8 hours. Mean contrast volume was 193 mL (range, 48-420 mL). Eight patients required a stay of </=4 days at the intensive care unit. Three patients died. Two deaths were procedurally related: one patient died of myocardial infarction, and the other had ischemic cerebellar stroke and died 3 months later of pulmonary sepsis. The third patient was readmitted 3 days after hospital discharge and died of alcoholic pancreatitis. One man had permanent paraplegia. Two women had transitory paraparesis. Striking hematologic and systemic inflammatory abnormalities were observed. CONCLUSIONS Increasing reports on stent graft technology indicate that this procedure might become a reality in the future for endovascular treatment of complex aneurysms in all aortic segments. Branched stent grafts seem to be feasible and can be offered as an effective alternative to most patients with TAAAs, especially for those who are currently excluded from open surgical procedures.