The differential diagnosis of hemoptysis includes a wide spectrum of infectious, autoimmune, and neoplastic diseases as well as chest trauma. The clinical presentation of a mycotic aortic aneurysm is often nonspecific, but mortality is high, especially after aneurysmal rupture. A high index of suspicion is warranted in any patient presenting with hemoptysis and a recent past history of subacute bacterial endocarditis, intravascular interventions, known aortic aneurysm, and/or immunocompromised state. A case report is presented of a patient with an ascending aortic mycotic aneurysm eroding into the adjacent lung, leading to chest pain, dyspnea, and hemoptysis. This case report provides an important lesson of the need to expand the differential