Transesophageal echocardiography (TEE) was used for the serial observation of a postoperative perivalvular abscess of a prosthetic aortic valve in a 65-year-old man who underwent aortic valve replacement for aortic regurgitation. Five months later, TEE revealed an aortic ring abscess. Ascending aortic grafting (Bentall method) and translocation of the aortic prosthetic valve were conducted for progressive mechanical valve dysfunction. Postoperative TEE showed flow between the left ventricular outflow tract and the abscess, which was unrestricted 1 month later. Associated clinical improvement suggested that washout of the abscess was a critical factor. This case illustrates the usefulness of TEE for examining postoperative aortic ring abscess.