Ultrasonography was used to explore surgical porto-caval shunt in 10 patients. In 9 of these, the patency demonstrated by angiography was confirmed, the communication between the two veins being clearly visible on 9 transverse sections, 6 sagittal sections and 2 right frontal sections. In addition, the echograms supplied information on the size of the opening, the calibre of the inferior vena cava (which was usually dilated below the anastomosis) and, in some cases, the presence of thrombosis. Harmless and readily accepted by the patients, ultrasonography is likely to become one of the preferred methods for post-operative control of porto-caval shunts.