Endoscopic ultrasonography within the stomach can provide high resolution images of the gastric wall as well as adjacent lesions that cannot be achieved with other diagnostic modalities. Clinically important uses include the evaluation of submucosal tumors, thickened gastric folds, changes seen with portal hypertension, and the staging of gastric malignancy. Two basic principles should be considered when applying this modality in clinical practice. The first is that for any test to be considered truly indicated, the results should have some significant impact on management decisions and/or quality of life for the individual. The second is that endosonographic imaging is not a substitute for histology, but findings may have a direct impact on the need for and methods of obtaining biopsy material.