Introduction. Thoracic aortic aneurysms (TAA) are the most common condition of the thoracic aorta requiring surgical treatment. Despite significant improvement in anesthetic, surgical techniques and postoperative care, the mortality and morbidity rate in TAA-repair remains high. The aim of this study was to assess the morbidity and mortality rate after endovascular stem-graft treatment of atherosclerotic (non-dissecting) TAAs. Methods. Thirty-one patients, ASA-classification III-IV, with symptomatic or expanding atherosclerotic TAAs underwent endovascular stent-graft repair between May 1997 and August 2003. Procedures were performed on an emergency basis in 13 patients and elective in 18 patients. Patients were assessed postoperatively by routine CT-scan within 48 h. Further follow up investigations were performed after 3, 6, 12 months and annually thereafter. Results. Stent-graft placement was successful in all but one patient in whom the stem-graft procedure had to be postponed due severe hemodynamic instability. Perioperative mortality rate was 19% including three haemorrhages, two cardiac events and one respiratory failure (6/31). Technical success rate was 55% (17/31). Completion CT scans performed in 30 patients within 2 days of stent-graft procedure showed type I leaks in seven patients (23%), type II leaks in four patients (13%) and type III leaks in two patients (6%). Further complications included one stroke, one paralysis, one spinalis anterior syndrome and five relevant access related complications. New onset endoleaks, all type I, were observed in seven patients (23%) occurring after 3, 4, 7, 8, 17, 25 and 26 months. Mean follow-up was 15 months (range 2-69 months). Conclusion. Thoracic aortic atherosclerotic aneurysm stem-grafting is feasible but not without significant morbidity and mortality.