Four cases of enormous shunt between portal and hepatic veins (portal-hepatic venous shunt) are reported with special reference to sonographic and portographic findings. Ultrasonography, an examination for screening, delineated a snail-like anechoic area in the liver, its connection with the portal and hepatic veins, and marked dilatation of the veins connecting with the shunt. Transarterial or percutaneous transhepatic portography, a method for definitive diagnosis, demonstrated large pooling of the contrast medium flowing from the dilated portal branch and subsequent visualization of the hepatic vein. The etiology and prognosis are unknown at present. The most likely pathogenesis for this shunt seemed to be a congenital anomaly, namely, persistence of the omphalomesenteric venous system. With recent advances in and the more frequent use of real-time ultrasonography, detection of this kind of vascular abnormality will doubtless increase.