Mechanical ventilation is an invasive life support procedure with manyeffects on the cardiopulmonary system.Ventilator injury and oxygen toxicity are thought to be importantfactors in the pathogenesis of chronic pulmonary disease.Assisted ventilation represents the hallmark of neonatal intensive care.Improvements in devices, the appearance of new techniques, better supportsystem, the development of exogenous surfactant, and otherpharmacological agents all have contributed to improving weight-specificsurvival rates for infants with neonatal respiratory failure.The aim of this study was to determine the incidence of Air leak syndromesof mechanically ventilated neonates as regards morbidity & mortality inNeonatal Intensive Care Unit, Children's Hospital-Cairo University duringthe years 2007-2008, and to correlate such outcome with gestational age,birth weight, indications and durations of mechanical ventilation.In this study neonates receiving mechanical ventilation (MV)accounted for (633 out of 3321) 19.06% of admissions, of whom (353 outof 633) 55.8% were males and (280 out of 633) 44.2% were females,outcome of mechanically ventilated neonates was (277 out of 633)43.76% discharged without any sequelae while (26 out of 633) 4.11%developed Pulmonary air leaks (PAL) (of them 6 (23.08%) dischargedwhile 20 (76.92%) died), three point five percent (22 out of 633)developed Bronchopulmonary dysplasia (BPD) (of them 11 (50%)discharged while 11 (50%) died) and (308 out of 633) 48.66% died notdue to PAL or BPD. Twenty six point one percent of cases (165 out of633) were managed with NCPAP alone while 45.8% (290 out of 633)required SIMV and 28.1% (178 out of 633) required combined NCPAPthen SIMV. Mean duration of ventilation by days with a mean of 7.13 ±6.56 days.From this study, we concluded that, the poor outcome of mechanicallyventilated patients is still a major problem in our community.Recognition and prevention of causes of airway injury can help toensure optimal outcomes for the critically ill neonate.