Respiratory distress syndrome (RDS) is one of the main causes of mortality in preterm infants. Surfactant treatment is a standard of care for infants who have RDS. Animal-derived surfactants in clinical use are obtained by organic extraction of porcine (poractant alfa) or bovine (beractant, surfactant-BL) minced lung or bovine lung lavage fluid (bovactant). Cochrane systematic review of randomised controlled clinical trials showed a similar efficacy of beractant and bovactant ininfants with RDS, while poractant alfa was more effective than beractant. In retrospective clinical study, poractant alfa in efficacy had advantages over surfactant-BL. Poractant alfa delivers the highest level of surfactant in the lowest volume and can be administered through the Less Invasive Surfactant Administration (LISA) technique using a thin catheter. Less invasive surfactant therapy reduces the need for mechanical ventilation in preterm infants.