Early onset pulmonary arterial hypertension in preterm is not uncommon and is associated with bronchopulmonary dysplasia and severe intraventricular hemorrhage. Inhaled nitric oxide was used to treat in majority of cases with good response and survival is high. Approximately 8-23% of premature infants develop pulmonary hypertension (PH), and this diagnosis confers a higher possibility of mortality. As a result, professional societies recommend PH screening in premature infants. However, the risk factors for and the outcomes of PH may differ depending on the timing of its diagnosis, and little evidence is available to determine at-risk infants in the referral neonatal population.Aim of this work: was to examine the risk factors and neonatal outcomes of early onset PAH (EOPAH) diagnosed in the first 2 weeks of age in preterm infants in a large perinatal center. Methods: This study was conducted on sequentially admitted preterm neonates in Benha children Hospital (130). A prospective observational study on neonates were admitted to neonatal intensive care unit allover 6 months since 1st of July to the end of December 2019. All the neonates were evaluated by echocardiogram between 72 hours and 14 days for early detection of pulmonary hypertension. Results: Regarding Early pulmonary arterial hypertension, Cases with early pulmonary arterial hypertension were 30 (23.1%) and Cases without early pulmonary arterial hypertension were 100 (76.9%). mean value of weight among Cases with early pulmonary arterial hypertension was lower than among Cases without early pulmonary arterial hypertension (1.68, 2.07) p value= 0.000 , we found that, regarding Maternal risk factors among cases with early pulmonary arterial hypertension, BA were 2 (6.7%), over weight mother was 3 (10%), hypertension was 1 (3.3%), prom was 1 (3.3%), irrelevant was 21 (70%) and Smoker mother were 2 (6.7%). regarding outcome, the percentage of die was higher among Cases with early pulmonary arterial hypertension than Cases without early pulmonary arterial hypertension (26.7%, 2%). P value= 0.000 .regarding fundus examination results was abnormal was 3 (10%) among cases with early pulmonary arterial hypertension. Regarding degree of pulmonary hypertension mild was 19 (63.3%), moderate was 10 (33.3%) and sever was 1 (3.3%). Conclusion: Our study shows that clinically significant EOPAH is present in 23.1% of preterm infants of less than 36 weeks GA. Our results shows that lower birth weights are associated with pulmonary hypertension. The mortality rate among the infants who affected with pulmonary hypertension was high. Regarding O2 Therapy, the percentage of Invasive MV was higher among Cases with early pulmonary arterial hypertension Hearing and fundus impairment occurred among cases with early pulmonary arterial hypertension.