Formation of the structure and topography of the coronary arteries during the fetal and early neonatal periods of human ontogenesis is an essential constituent while making perinatal diagnosis and understanding real parameters of the norm and pathology. Objective of the study is to determine organometric parameters of the carotid arteries during the fetal and early neonatal periods of human ontogenesis. The study was conducted on 50 specimens of dead fetuses (from 4 to 10 months) and 9 neonates (5 isolated complexes of organs in particular) by means of adequate anatomical methods: macrodissection, injection of the blood vessels, making topographic-anatomical sections, morphometry, and statistical analysis. During perinatal period external diameters and lengths of the carotid arteries are found to be characterized by two periods of an accelerated development and the period of relatively slow development. For the external diameter of the right common carotid artery and the external diameter of the left internal carotid artery the periods from the 4th to 7th months of the intrauterine development and the period from the 9th month to the neonatal period are the periods of an accelerated development; the periods from the 7th to 9th months of development are the period of relatively slow development. The periods from the 4th to the 7th months of the intrauterine development and the period from the 10th month till neonatal period are the periods of an accelerated development for the external diameter of the left common carotid artery and external diameter of the right internal carotid artery; the period from the 7th to the 10th months of development is the period of relatively slow development. The periods from the 4th to the 7th months of the intrauterine development and from the 8th month of development till the neonatal period are the periods of an accelerated development for the external diameter of the right and left external carotid arteries; the period during 7-8th months is the period of relatively slow development. The length of the cervical part of the right and left carotid arteries is characterized by the two periods of an accelerated development – from the 4th to the 6th month and from the 7th month till the neonatal period; the period of relatively slow development is from the 6th to the 7th month of the intrauterine development. Comparison of the developmental periods of the carotid arteries with all the possible organometric parameters enables to affirm that practically similar enlargement of the external diameters of the common, external and internal carotid arteries both from the right and left sides is peculiar for the period of relatively slow development. The first period of an accelerated development of the carotid arteries is more specific for the external diameter and length of the left common and left external artery contrary to the second accelerated period of development of the carotid arteries. It is characterized by enlargement of the external diameters of the right common and right external carotid artery. A reliable difference of the mean values of the external diameters of the right and left common, external and internal carotid arteries is peculiar for the 4th, 7th, 10th months of development and for the neonatal period for the common carotid arteries; for the external carotid arteries – the 4th, 7th, 9th months of development and neonatal period; for the internal carotid arteries – for the whole months of development.