Background: Carnitine is one of hydrophilic amino acid derivatives participating in pulmonary surfactant production in infants. The deficiency of Carnitine might lead to the incidence and severity of respiratory distress syndrome [RDS] in preterm infants.  
Aim of the work: The aim of this work is the assessment and evaluation of L- carnitine therapy effect on the prognosis of respiratory distress syndrome.
Patients and Methods: The study included a total number of 90 preterm infants with RDS, categorized into two groups; group I [40 cases] with sufficient level of l-carnitine and group II [50 cases] with deficient l-carnitine. Both groups are subdivided into two subgroups; intervention group [received carnitine] and control group. Patients with sufficient carnitine levels received Carnitine supplementation at a dose of 10 mg/kg/day. Patients with deficient carnitine levels received Carnitine therapy at a dose of 30 mg/kg/day Follow-up was carried out to assess the need of respiratory support, oxygenation, hospital stay and mortality.
Results: The mean gestational age was 31.62 ± 2.18 wks. The mean birth weight was 1.58 ± 0.41 Kg. Newborns with deficient carnitine level were had lower birth weight [1.68 ± 0.42 Kg vs. 1.50 ± 0.39 Kg; P=0.046] and exhibited more frequency of mechanical ventilation [P=0.021]. In the sufficient Carnitine group, carnitine supplementation was associated with improvement of weight [P=<0.001] and early onset of enteral feeding [P=0.013]. In the deficient carnitine group, carnitine supplementation was associated with lower need [P=0.031] and short duration [P=0.006] of mechanical ventilation.
Conclusion: The supplementation of Carnitine for infants with sufficient carnitine has a significant positive effect on their growth and weight gain. Carnitine therapy for infants with deficient carnitine significantly reduces mechanical ventilation requirement and duration, improved chest X- ray, shortened duration to reach full enteral feeding and the duration of neonatal intensive care unit [NICU] stay.