We report a case of a middle-aged woman in whom a transesophageal echocardiogram showed a mass-like lesion posteriorly near the descending thoracic aorta. We were able to make a definitive diagnosis of this mass as a hiatal hernia because of a thick inner lining measuring 6-9 mm in thickness similar to the stomach mucosa, and the presence of a few microbubbles within the mass. In addition, the microbubbles increased considerably after 10 cc of agitated normal saline flush via a nasogastric tube.