During the past 20 years, transesophageal echocardiography (TEE) became an important diagnostic technique. Indications for TEE include: defining the cause and severity of native valve disease, particularly mitral regurgitation; detecting vegetations and other sequelae of endocarditis; assessing prosthetic valve function; and identifying a potential cardiac source for emboli.(1) TEE is usually well tolerated and is associated with few adverse events. However, structural abnormalities of the esophagus such as diverticula, stenoses, tumors, and advanced varices are relative contraindications to TEE because of the technical difficulties associated with probe advancement and the risk of esophageal perforation.(2) This report describes the successful performance of TEE in a patient with a Zenker's diverticulum. The patient was severely symptomatic of atrial fibrillation and was a poor candidate for long-term anticoagulation. Therefore, it was necessary to rule out a thrombus before cardioversion. Because the Zenker's diverticulum was large, a novel approach was taken using a balloon to occlude the orifice allowing safe passage of the TEE probe.