We evaluated the use of real time linear echotomography to diagnose cancer affecting the wall of the stomach. In vitro studies were performed on pieces resected from normal subjects and patients with peptic ulcer or gastric cancer. 108 patients were also evaluated, 68 with normal findings at endoscopy and radiology and 35 with gastric cancer. The muscularis mucosae and the muscular layers are hypoechogenic while the mucosa, submucosa and subserosa are echogenic. An infiltrative process leads to alteration of these echographic layers which are replaced by an hypoechogenic zone. Depth and extension of the lesion may thus be evaluated. Routine analysis of the gastric wall in every echographic examination of the abdomen may help detect early cases of gastric cancer.