Aims: To evaluate the relationships between postnatal passive respiratory compliance (Crs) and development of respiratory disorders during the first 6 month of life in preterm and full term infants after respiratory insufficiency. The purpose of this study was to investigate whether other relevant neonatal factors, like degree of prematurity, birth weigh, ventilatory conditions, sepsis, and respiratory disease severity affected this relationship. Material and methods: The passive respiratory compliance was measured by the single occlusion technique in 73 preterm infants after respiratory distress syndrome (RDS), 19 full term infants after congenital pneumonia and 33 healthy full term infants. Respiratory function measurements were performed by single occlusion technique, during natural sleep, after acute phase of illness, before discharge from neonatal department. Results: Crs was significantly lower in premature newborns <36 weeks gestation after RDS (p=0,0002) and in term newborns who have suffered from a congenital pneumonia (p=0,0411), than in healthy full term newborn infants. Premature infants who have undergone sepsis have significantly decreased Crs in relationship with those who did not have this complication (p=0,0334). Preterm newborns who have suffered pneumonia during treatment of RDS have significantly frequent respiratory problems during the first 6 month of age ; (p=0,043). Full term infants after congenital pneumonia have more but not significantly frequent respiratory problems than healthy term newborns (p=0,055). Decreased neonatal Crs wasn’t significantly related to respiratory disorders in age of 6 month of life. Conclusion: Decreased neonatal Crs in premature and full term infants after respiratory insufficiency wasn’t significantly related to respiratory disorders during first 6 month of life. This study has showed significantly increase of respiratory problems in this period in preterm and full term infants who have suffered from pneumonia during neonatal period.