Venous blood fl ow in the liver is unique because it is provided by two embryonic and functionally diff erent systems: the umbilical and portal hepatic or yolk systems.The largest tributary vessel of the liver in pre-fetuses is the umbilical vein (UV), which passes through the gap of the round ligament of the liver and gives from 2 to 5 branches to the left side of the liver and the same number to the square. At the level of the left edge of the transverse sulcus, the UV is divided into three termin branches: the posterior branch to the left lobe, the venous (Arantian) duct, and the anastomotic branch, through which the UV connects to the portal hepatic vein (PHV).To study the patterns and identify the features of the intrahepatic topography of venous structures, in particular the umbilical vein in the prefetal period of human ontogenesis.For the study, 50 objects of pre-fetuses were used. To achieve this goal, a complex of morphological research methods was used, including the method of morphometry, the production and study of a series of histological sections, macro- and microscopy, conventional and fi ne preparation under the control of an MBS-10 microscope, injection of vessels with the following radiography.At the beginning of the prefetal period of development (VII week), the liver occupies the cranioventral and middle sections of the abdominal cavity. Its transverse dimension is 4.8 mm (pre-fetus 19.8 mm of parietalcoccygeal length (PCL)) and 5.1 mm (pre-fetus 20.0 mm PCL).UV of pre-fetuses of the 7th week of development (14.0-20.0 mm PCL) was studied on 16 series of histological sections. It enters the liver in the area of the anterior edge of the left sagittal groove and is covered from below by the liver tissue. Along the way, it gives off 2-3 left side branches with a diameter of 40-50 microns, branching in the left lobe of the organ, and 1-2 right ones, entering the square lobe. The UV enters the liver parenchyma in the area of the anterior edge of the left sagittal sulcus and passes in the anterior- posterior direction within its anterior part. From below, the vein is covered with liver tissue.The outer diameter of the UV at the edge of the liver is 370 μm (pre-fetus 30.0 mm PCL), its length reaches 940 μm.In the course of the UV, it gives off 2-3 left lateral branches with a diameter of 98-102 microns, branching in the left lobe of the liver, within the future II, III and partially I and IV segments, and 1-2 right ones, entering the square lobe, ending in the future IV segment.Consequently, at the end of the prefetal period of development, the intrahepatic topography of the aff erent venous vessels (umbilical and portal veins) and their branches of 1-2 orders acquires certain features of the defi nitive one.