Background: Managing ventilation and oxygenation during laparoscopic procedures in morbidly obese patients undergoing surgery represents many challenges. There is no specific guideline on the ventilation modes for this group of patients. Although several studies have been performed to determine the optimal ventilatory settings for those patients, the answer is yet to be found. The aim of this study was to determine which mode of ventilation is more effective in improvement of intraoperative oxygenation and prevention of postoperative pulmonary atelectasis with its consequences is PEEP 10cmH₂O alone is effective or Recruitment maneuver followed by PEEP 10 cmH₂O has better results.Aim of the Work:The study will be performed to compare different intra-operative ventilatory techniques that prevent early postoperative pulmonary complicationsespescially atelectasis in obese patients undergoing laparoscopic surgery.Patients and Methods:Thisprospective, interventional, therapeutic, randomized clinical studywas conducted at Ain Shams University Hospitals, operating theatre department on 100 morbidly obese adult patients of ASA physical status II, admitted to Ain Shams university hospital, scheduled for elective laparoscopic surgery either bariatric or non-bariatric. The study was carried out after approval of the departmental ethical committee.The patients were subdivided into 4 groups A, B, C and D, (25) patients for each group. Results: Regarding the value of PO2/ Fi O2, there is no statistically significant difference between all groups in the preoperative and intra operative values. But there is statistically significant increase in group D and group C respectively compared to group A and B in both post-operative and 6 hours post-operative values. Regarding CT chest,Group A showed the highest number of both lobar and segmental atelectasis followed by group B which showed also a high number of segmental atelectasis. In despite, group C showed a higher number of plate and lamellar atelectasis followed by group D that showed a high number of lamellar atelectasis but the lowest number of other atelectasis scores. Conclusion: In conclusion, repeated Recruitment Maneuvers combined with 10 cmH2O of PEEP have beneficial effects on oxygenation continued into the early recovery period and decrease pulmonary complications in the early post-operative period in morbid obese patients undergoing laparoscopic surgery. Recommendations: Further studies on a larger scale of patients are needed to confirm the results obtained by this work.