Seventy-five newborn babies from neonatal intensive care unit (NICU) of Yuzuncu Yil University Medical Scholl (Van, Turkey) will be randomized to treatment with nebulized surfactant (Curosurf®, Chiesi Pharmaceutics, Parma, Italy) or to two control groups receiving INSURE and MIST method. The study will be conducted with 75 infants, 25 in each group. Randomization will be central and performed using sealed envelopes kept at the neonatal ward of Yuzuncu Yil University Medical Centre Hospital. Informed consent was obtained from all parents before randomization. Inclusion criteria are corrected gestational age >26 week or <34 week, age 2-36 h, clinically and radiologically diagnosed progressive RDS, FiO2 needed to maintain SaO2 85-95%; >0.4, and no evident lung or cardiovascular malformation.