The data of renal ultrasonographic and Doppler studies were comparatively assessed in children with congenital hydronephrosis. The degree of renal B-mode ultrasound hemodynamic parameters was used as the basis for grouping of the children. The resistance index (RI) of all branches of renal arteries receives attention. Morphological studies were carried out on renal biopsy specimens from 29 children from different groups and on 12 removed kidneys; the expression of TGF beta1 and alphaSMA was revealed using the streptavidin-biotin-peroxidase method. Morphological changes as hypoplasia or dysplasia became more pronounced from Group 1 to Group 3, RI increasing to peak in Group 3. Vascular changes were confined to compensatory processes following the pattern of remodeling that was manifested by vascular wall thickening and a gradual increase in RI. Failing compensatory processes resulted in the development of renal functional and hormonal decompensation and in the elevation of RI. There was a coupling between the magnitude of morphological changes and RI increases. A set of the findings emphasizes the undoubtedly important role of renal ultrasound study that makes it possible to judge the state of the vascular bed and to suggest renal structural problems in congenital hydronephrosis.