The present study was designed to evaluate, in premature babies with RDS breathing spontaneously, the efficacy of combined treatment with nasal continuous positive airway pressure (CPAP) and aerosolized surfactant. The first objective of investigators is to assess the safety of surfactant nebulization in this clinical situation, and to ﬁnd out whether treatment with aerosolized surfactant would reduce the need for mechanical ventilation. And other aim suggest that aerosolized dates compared with dates of INSURE (intubation-surfactant-extubation) and minimally invasive surfactant therapy (MIST) method.