Persistent pulmonary hypertension of the newborn (PPHN), it is characterized by failure of the normal postnatal fall in pulmonary vascular resistence, it can cause both immediate and long term complication. There are various modalities for treatment of PPHN. ECMO & INO are effective in treatment of PPHN but not available in developing countries. Our study was done to light the comparison between the effects of oral sildenafil and magnesium sulfate in the treatment of PPHN. Our study is prospective cohort review included 20 neonates. The neonates were divided into two groups: the first group represented 10 neonates treated with sildenafile, whereas the second group represented 10 neonates treated with magnesium sulfate. We found a statistically significant difference (P value 0,014) in estimated pulmonary artery pressure after another 3 days of treatment by sildenafil or magnesium sulfate. We also revealed that good improvement in Sao2&ABG with two groups but earlier in sildenafil group. Limited side effects and good outcome was observed in both groups.Conclusion: we concluded that MgSo4 can be used as an alternative treatment to sildenafil in treatment of PPHN in Egypt.