Gastroscopic ultrasound tomography enables a direct sonographic approach to the upper gastrointestinal tract and the surrounding organs. First experiences show that this new method is characterised by a great diagnostic potential. Its advantages compared with conventional sonography are the avoidance of sonographic obstacles and an improved recognisability of details; part of the examined area is, so to say, enlarged due to the use of high ultrasonic frequencies. With an ultrasonic frequency of 7.5 megahertz, the following processes can be visualised more clearly than with conventional sonographic equipment: processes in the pancreas, cholelithiasis of the common bile duct, hepatic foci, processes in the splenorenal angle, as well as tumours of the stomach and of the esophagus. In cardiology, clear indications are easily recognised, such as the atrial septal defect.