Objective: Mycotic aortic aneurysms are rare, life threatening, and complex. This nationwide study aimed to assess outcome after repair of mycotic thoracic aortic aneurysms (MTAAs). Methods: Patients treated in Sweden for MTAAs between 2000 and 2016 were identified in the Swedish vascular registry (2010-16) and local patient registries (2000-09). Primary outcome was survival, and secondary outcomes included surgical strategy, rate of infection related complications (IRC), and re-operations. Results: Fifty-two patients (median age 71 +/- 8.1 years; 28 [54%] men, 13 [25%] ruptured) were identified (3.6% of all thoracic aortic aneurysm repairs in Sweden). Aneurysm location was aortic arch (n = 6; 11%), descending aorta (n = 42; 81%), and multiple locations (n = 4; 8%). Twenty-nine (56%) patients had positive cultures; the most prevalent agent was Staphylococcus aureus (n = 16; 31%). Operative techniques included thoracic endovascular aortic repair (TEVAR; n = 35 [67%]), fenestrated/branched TEVAR (n = 8; 15%), hybrid repair (n = 7; 14%), and open patch repair (n = 2; 4%). Survival was 92% (95% confidence interval [CI] 88-96) at 30 days, 88% (95% CI 84-93) at three months, 78% (73-84) at one year, and 71% (64-77) at five years. The mean follow up among survivors (amp;gt; 90 days) was 45 months (range 4-216 months). Antibiotics were administered for a median of 15 weeks (range 0-220 weeks). IRCs occurred in nine patients (17%): sepsis (n = 3), graft infection (n = 3), recurrent mycotic aneurysm (n = 1), aorto-oesophageal/bronchial fistula (n = 2). Six (67%) IRCs were fatal; 80% occurred within the first year. Re-operations were performed in nine patients (17%). Conclusions: TEVAR was often used as treatment for MTAAs, with acceptable short- and long-term survival when compared with open cohorts in the literature. IRCs are of concern and warrant follow up and long-term antibiotic treatment.