Background: A correlation has been shown between atelectasis and the magnitude of shunt. It is not known if the amount of atelectasis may be reduced by passive inflations of the lungs and at what extent of inflation this occurs.Aim: This study will be done to compare the effect of PEEP versus the effect of PEEP with recruitement maneuver during general anesthesia in improving the arterial oxygenation and lung compliance.Material and Methods: Our study includes 60 patients assigned randomly into one of the three equal sized groups.Group I: Patients will continue with the same ventilator settings as during the control period and no PEEP will be given (Control group).Group II: After the control period of 30 min, PEEP equal to 5cm H2O will be added to the ventilator circuit.Group III: After the control period of 30 min, PEEP equal to 5cm H2O will be added and at the conclusion of surgery, recruitment will be done.Conclusion: Addition of PEEP to the ventilator circuit during routine anaesthesia conduct would reverse anaesthesia induced atelectasis and improve arterial oxygenation and lung compliance; moreover, addition of recruitment maneuver (Sustained increase in airway pressure with goal to open collapsed lung tissue) during general anaesthesia would further improve arterial oxygenation and lung compliance.