A case of bacterial aortitis of the ascending aorta caused by Staphylococcus aureus progressed to an aortic mycotic aneurysm. Transesophageal echocardiography was the diagnostic approach of choice. The different stages of the disease from the initial aortic wall infection to formation of an abscess that communicated with the aortic lumen were documented by transesophageal echocardiography.