Aim. To study the ultrasonographic parameters of segmental function and mechanics of the aorta and carotid arteries in healthy infants.Methods. We observed 114 healthy infants (age range, 1–12 months; boys 52.6%; mean body surface area (BSA): 0.35 ± 0.8 m2). Echocardiography was performed with an Acuson S 2000 (Siemens Medical Systems, Mountain View, CA, USA) using vector velocity imaging (VVI). The following parameters were estimated at the level of the ascending and abdominal aorta and in the common carotid arteries (CCA): maximum and minimum diameters (mm); circumferential strain (CS, %) and circumferential strain rate (CSR, s-1); fraction area change (FAC, %); arterial stiffness (β2).Results. The maximum and minimum diameters of the examined segments of the aorta and CCA, FAC of the aorta and CCA, CS and CSR of the aorta and CCA showed a correlation with BSA, age, LV stroke index, and LV myocardial mass index. None of the estimated parameters showed a correlation with sex, arterial blood pressure, or left ventricular ejection fraction. The highest CS values were found in CCA 7.85 ± 2.8% [compared with 5.4 ± 0.98% (p = 0.0001) in the ascending aorta and 6.7 ± 1.8 % (p = 0.03) in the abdominal aorta). CSR in the CCA (0.84 ± 0.22 s-1) was significantly higher than that at the abdominal aorta level (0.67 ± 0.24 s-1, p = 0.001), but lower than that in the ascending aorta (1.3 ± 0.3 s-1, p = 0.00001).Conclusion. The parameters of segmental function of the aorta and common carotid artery obtained in our research can serve as normative reference for children in the first year of life. The functional parameters of the aorta and common carotid artery depend on the age and BSA. Received 15 December 2019. Revised 26 February 2020. Accepted 27 February 2020. Funding: The study did not have sponsorship. Conflict of interest: Authors declare no conflict of interest.