Ultrasonic detection and measurement of the abdominal aorta can be accomplished accurately and quickly. Sections of the aorta obtained at autopsy were measured and subsequently immersed in water and studied by ultrasound. Ultrasonic aortography was performed on patients with suspected cases of abdominal aneurysm and the results compared with those obtained from contrast aortography. In four instances in which the patients came to surgery, the actual specimens were available for comparison and measurement. Preliminary results indicate that ultrasonic measurements of the aorta compare favorably with those obtained by contrast aortography and actual caliper determinations.