Background: To characterize hemodynamics in the first 24 h after birth in neonates with severe anemia. Method: This was a retrospective analysis of data from a prospective cohort from our critically ill neonate database, that included neonates with severe anemia from December 2022 to June 2024. The results obtained from neonates with severe anemia and the control group werecompared. Results: A total of 21 neonates born at 37 [35.00, 38.00] weeks and weighing 2780 [2350, 3200] grams were included. Compared with the control group, we observed lower peak systolic myocardial velocity in biventricular (left: 5.67 [5.43, 6.48] vs. 6.6 [6.12, 7 .32], p < 0.001; right: 6.33 [5.72, 7 .48] vs. 8.02 [6.74, 8.86], p < 0.001). A greater ratio of the tricuspid valve early inflow velocity/early diastolic myocardial velocity was noted (6.63 [5.92, 9.27] vs. 5.31 [4.67 , 6.55], p < 0.001). The peak systolic blood flow of middle cerebral arteries was greater (left: 55.90 [47 .10, 64.90] vs. 44.95[38.20, 50.95], p = 0.008; right: 52.00 [40.88, 56.15] vs. 45.20 [38.00, 52.00], p = 0.048). The lung ultrasound score was 18.00 [13.5, 25.5]. Conclusion: Neonates with severe anemia are characterized by reduced cardiac systolic function, reduced right diastolic function, increased cerebral blood flow , and pulmonary edema during the transition period.