Introduction: Aging is a continuous process, which leaves its mark on all tissues, organs and organ systems. The aging process causes a number of functional and morphological and structural changes in the kidneys. Objective: The aim of our study was to analyze echotomographic changes in the size of the renal parenchyma and renal sinus during the aging process. Method: The study was conducted on 62 subjects in the service of the radiological diagnostics of CHC Dr Dragisa Mišović in Belgrade. All subjects included in this study were neither anamnestically nor echotomographically positive for any of kidney diseases. Subjects were assorted in three age groups. Group I (20-39 years) - 21 subjects, group II (40-59 years) - 21 subjects, and group III (60-79 years) - 20 subjects. Results: During aging process dimensions of the renal parenchyma decrease. Dimensions of the renal parenchyma exhibit statistically significant difference (p<0.05) between the first and third age group for both kidneys, but difference between the first and second age group is significant only for the right kidney (p<0,05). Dimensions (length and width), of the renal sinuses tend to increase during the aging process, with difference between the first and third age group that is statistically significant for both kidneys (p<0.05). Difference in width of the sinuses for both kidneys is statistically significant only between the second and third age group. Conclusion: During aging process size of the renal sinus increases at the expense of renal parenchyma, and parenchyma-pyelon index decreases.