Objective: Our goal was to determine whether endovascular stent- grafting is feasible and effective for patients with aneurysms of the descending thoracic aorta. Methods: Starting in July 1992, we conducted a prospective, uncontrolled clinical trial in 103 patients (mean age 69 years [range 34-89 years]) who underwent endovascular treatment of aneurysms of the descending thoracic aorta using a custom-fabricated, self-expanding stent- graft device. Follow-up was 100% complete and averaged 22 months. Sixty-two patients (60%) were judged not to be reasonable candidates for a conventional 'open' surgical procedure. Results: Complete thrombosis of the aneurysm was ultimately achieved in 86 (83%) patients. The early mortality rate was 9% ± 3% (±70% CL). Multivariable analysis revealed that myocardial infarction or stroke was linked with a higher likelihood of early death (P = .001). Early serious complications included paraplegia in 3% ± 2% and stroke in 7% ± 3%. Actuarial survival estimates at 1 year and 2 years were 81% ± 4% and 73% ± 5% (±1 SE), respectively; being judged not to be a surgical candidate portended a higher probability of death (P = .003). According to the intent- to-treat principle, 'treatment failure' (including all late sudden unexplained deaths) occurred in 38 patients; 53% ± 10% of patients were free from treatment failure at 3.7 years. Stent-graft related complications occurred commonly and were linked with several anatomic, technical, and patient-related risk factors. Conclusions: This 5-year clinical trial involving use of a 'first generation' device indicates that endovascular stent-grafting of descending thoracic aortic aneurysms is feasible with acceptable medium-term results. More refined, commercially developed devices available today offer less traumatic and more precise stent-graft deployment; these major technical advantages, coupled with important lessons we have learned over time and better patient selection, should be associated with more salutary clinical results in the future.