Objective: Determine plasma NT-ProBNP concentration in the neonatal period. Objects and methods of the study: Prospective, cross-sectional study on 96 children from 1 day to 28 days at the Vietnam National Children's Hospital. Quantifying the plasma NT-ProBP concentration and comparing between age groups, gender, and preterm – full-term infants. Results: NT-ProBNP concentration was highest at 1 day of age and then gradually decreased with age with a statistically significant difference (p<
0.05). There is a negative linear correlation between NT-ProBP concentration and age (r = -0.82
p <
0.05). There was no difference in NT-ProBNP concentration according to gender (p>
0.05). NT-ProBNP concentrations in preterm infants were higher than in full-term infants (p<
0.05). Conclusion: NT-ProBNP concentration increases after birth and gradually decreases with age. There were differences in NT-ProBNP concentrations between full-term and preterm infants but no differences by gender.