The potential of medical therapy to influence the courses and outcomes of patients with thoracic aortic aneurysms is not known. The aim of this study was to determine whether statin intake is associated with improved long-term outcomes in these patients. A total of 649 patients with thoracic aortic aneurysms were studied, of whom 147 were taking statins at their first presentation and 502 were not. After a median follow-up period of 3.6 years, 30 patients (20%) taking statins had died, compared with 167 patients (33%) not taking statins (hazard ratio 0.68, 95% confidence interval 0.46 to 1, p = 0.049); 87 patients (59%) taking statins reached the composite end point of death, rupture, dissection, or repair compared with 378 patients (75%) not taking statins (hazard ratio 0.72, 95% confidence interval 0.57 to 0.91, p = 0.006). After adjustments for co-morbidities, the association between statin therapy and the composite end point was driven mainly by a reduction in aneurysm repairs (hazard ratio 0.57 95% confidence interval 0.4 to 0.83, p = 0.003). On Kaplan-Meier analysis, the survival rate of patients taking statins was significantly better (p = 0.047). In conclusion, the intake of stains was associated with an improvement in long-term outcomes in this cohort of patients with thoracic aortic aneurysms. This was driven mainly by a reduction in aneurysm repairs.