Background: Transient tachypnea of the newborn(TTNB) is a common cause of respiratory distress in the postnatal period. It is rarely associated with serious complications that need intensive care. Prediction of the complications during the first hours of hospitalization is very difficult, so the purpose of the current study is to investigate the relationship between lactate dehydrogenase (LDH) level in blood and the course of Transient tachypnea of the newborn (the duration of hospitalization, and the incidence of complications).Material and methods: In a cross-sectional study design included 120 neonates with Transient tachypnea of the newborn who had referred to the Neonatal Intensive Care Unit (NICU) at Tishreen University Hospital over 1 year period from January 2018 to January 2019. The neonates were classified according to Lactate dehydrogenase measurement as normal or high lactate dehydrogenase level in blood.Results: The results showed that there was a significant relationship between the level of lactate dehydrogenase and the duration of hospitalization, the incidence of complications, and the frequency of complications.Conclusions: lactate dehydrogenase might be useful for clinicians to predict the duration of hospitalization and the incidence of complications in neonates with TTNB.