Background: N-terminal pro-BNP, the inactive by-product of Pro-BNP which is secreted from Ventricular cardiomyocytes in response to volume or pressure overload, is more stable in serum sample and has a longer half-life in circulation than active form BNP. The study aimed to determine whether there was a correlation between plasma NT-proBNP level and echocardiographic assessment of ductal diameter and shunting to early predict cases that need treatment to decrease morbidities and mortalities of HSPDA or not. Methods: The study was cohort control study performed on 30 preterm infants (20 males, 10 females) ages (28w to ≥ 37w) and admitted to Neonatal Intensive Care Unit at Zagazig University Children Hospital during the period from November 2017 to April 2018, were divided into 2 groups, Group 1: Comprised 13 neonates and they had HsPDA. Group 2: enrolled 17 cases and they had non HsPDA. Chest x-ray were done, Echocardiography (ECHO) at postnatal 48–72h using a vivid 7 dimension (general electric machine) Transthoracic complete M-mode, two-dimensional and Measurement of Plasma level of N-Terminal pro BNP is measured at day 1,2 and 3 by Elisa biomedica kits. Results: There was a significant positive correlation at day 2 between N-terminal pro BNP and PDA Diameter. Moreover, ROC Curve detected that the cut off value for diagnosis of HsPDA was ≥ 4.55 pg/ml. Conclusion: N-terminal pro BNP can be considered as a sensitive diagnostic marker for detection of HsPDA and can be used early at day 2 for early diagnosis and proper management of HsPDA.