The aim of this preliminary study was the estimation of renal blood flow in 16 premature newborns from twin pregnancies with mean body weight 1270 g and mean gestational age 29 weeks. In control group we have 16 singleton newborns with mean gestational age 29 weeks and mean birth weight 1240 g. In both intervention and control group we have the similar clinical symptoms. The renal blood flow was carried out in the first day of life with the Acuson 128 XP Colour Doppler using the 6 and 7 MHz linear transducer. The renal blood flow parameters-PI, RI, Vmax, Vmin Vmean were measured in right and left renal arteries in theirs courses from the aorta to the renal hilus, by color sinal. In the investigation group the mean value of RI in right and left renal artery was 0.88. Mean PI in right vessel was 1.67 and in left 1.56. Mean V min in right and in left artery was 0.03 and mean V max in right artery was 0.34 and in left 0.33. Mean value of mean velocity in right vessels was 0.18 and in left 0.19. In control group we observed in right artery mean value of PI 1.74 and in left 1.6. Mean RI was 0.86 and 0.86 in right vessel in left vessel. Mean V min was 0.05 in right and 0.04 in left artery. Mean V max was 0.37 in right and 0.34 in left artery. Mean value of V mean was 0.19 in right artery and 0.18 in left artery. Using the student, Mann-Whitney and Shapiro-Wilk tests we have not observed statistically significant difference of Doppler parameters between control and investigation group and between the left and right artery. Although in newborns with broad PDA we noted significant higher value of RI (0.97, 0.98) than in newborns without PDA (0.78, 0.81).