Objective: to determine therapeutic effect of surfactant injection through tracheal in hospitalized newborn infants with respiratory distress syndrome in Amiralmomenin hospital in Semnan. Study design: non-randomized, Parallel-group, and without placebo. single-center. Inclusion criteria: premature infants admitted to the neonatal intensive care unit with a definite diagnosis of respiratory distress syndrome, age ≤ 24 hours. Exclusion criteria: infants with major abnormalities, chromosomal abnormalities, severe asphyxia, need to intubation at birth. Statistical population: all newborns with respiratory distress syndrome. Method of execution: surfactants administration via endotracheal tube. Clinical Guide of surfactants administration will be accordance to Aguar and colleagues study in 2014. Data collecting tool: 1. gestational age, gender, singleton or multiple pregnancy, maternal risk factors, birth weight, birth length and head circumference at birth, method of delivery, one and five-minute Apgar birth number, receiving cortons before birth by mothers and analysis of blood gases arterial at first hour of birth 2. Check list of data records based on RDS score, intensity of respiratory distress based on the X-ray, neonatal mechanical ventilation, surfactant dosage, age of prescribed surfactant (h), length of stay, patient outcomes (death / improvement) , Complications.