Background Mycotic thoracic aortic aneurysms are a life-threatening diagnosis and carry a high risk of morbidity and mortality in the perioperative setting. Traditional open repair consists of debridement, drainage, and either in situ or extra-anatomic bypass. Acute rupture portends a dismal prognosis; however, emergent endovascular repair of ruptured mycotic aneurysms has been described in the literature and we present a case of successful endovascular treatment of a ruptured mycotic descending thoracic aortic aneurysm. Case Report We report the case of a 42-year-old male with hypertension and active intravenous drug use who presented with 3 weeks of chest pain, dyspnea, and hemoptysis, and on computed tomography scan was found to have a contained 4.1-cm ruptured mycotic thoracic aortic aneurysm. Blood cultures were positive for methicillin-resistant Staphylococcus aureus. Emergent repair was recommended because of likelihood of further rupture and death. Thoracic endovascular aortic repair (TEVAR) was performed using a rifampin-soaked stent graft without complication. At 2-year follow-up, the patient was asymptomatic and imaging demonstrated the stent graft in excellent position, without endoleak, and complete resolution of the aneurysm sac. Conclusions TEVAR can be safely employed to treat a ruptured mycotic thoracic aneurysm when open repair is not possible because of patient's comorbidity or complex rupture, as these patients face imminent death. Long-term follow-up is necessary for detection of endoleak, recurrence, or propagation of the aneurysm, and persistent bacterial infections.