Objective To assess the effect of lung protective ventilation on outcome of children with acute respiratory distress syndrome(ARDS).Methods Between January 1999 and December 2007,43 children with ARDS were enrolled from PICU of Shanghai Children's Medical Center and assigned to the protective-ventilation group(group A) or the conventional-ventilation group(group B).The patients in group A (from January 2004 to December 2007)received lower tidal volume(6～7 ml/kg) and high levels of positive end-expiratory pressure(PEEP),and optimal oxygenation was achieved by adjusting FiO2 and PEEP.The patients in group B(from January 1999 to December 2003) received relatively higher tidal volume(8～12 mL/kg) with lower PEEP(2～6 cm H2O),and optimal oxygenation was achieved by adjusting FiO2.Tidal volume,PEEP,arterial blood gas,mortality and the number of ventilator-free days were compared between the two groups.Results Since protective ventilation was adopted after 2004,tidal volume was significantly lower in group A[(7.09±1.66)ml/kg]as compared with that in group B[(9.82±2.31) ml/kg](P=0.001).PEEP was significantly higher in group A[(7.15±2.08) cm H2O]as compared with that of group B[(5.40 + 1.84) cm H2O](P=0.021).The mortality was 30.3% in group A and 60.0% in group B.The number of ventilator-free days were(10.88±8.84) d in group A and(8.40±10.86) d in group B.Although mortality was lower and number of ventilator-free days was greater in group A,no significant differences were found between the two groups(P＞0.05).Conclusion Lung protective ventilation may improve the outcome for pediatric patients with ARDS,however,larger trials are required before a definite conclusion can be reached.