Many cases undergoing abdominal surgery under the influence of general anesthesia develop atelectasis. Effects of ventilation on lung perioperatively could be easily assessed using ultrasound. Aim: this study was conducted to evaluate whether using PEEP with or without recruitment maneuver could reduce perioperative lung atelectasis using ultrasound in major upper abdominal surgeries. Methods: 117 individuals who were set to have open upper abdominal surgery were split into three groups; Low PEEP group (4 cm H2O), High PEEP group (10 cm H2O) and High PEEP with recruitment maneuver group [10 cm H2O + RM (30 cm H2O for 30 s) every 30 min]. At six different predetermined time periods, ultrasonography of the lungs was performed. The primary result was a variance in lung ultrasonography (LUS) score amongst the groups preceding emergence. Results: LUS score before emergence was considerably lesser in High PEEP with recruitment Maneuver group than other 2 groups (P= 0.02). This difference started to vanish after extubation (P=0.08). PaO2/FiO2 ratio was considerably greater in High PEEP with recruitment Maneuver group than other 2 groups before emergence. No difference between the 3 groups regarding PPCs was found. Conclusions: Adding recruitment maneuver to high PEEP during open upper abdominal surgeries caused less atelectasis and loss of lung aeration by the end of surgery as assessed by LUS and more enhancement of P/F ratio than when PEEP was used alone. However, it didn’t affect the rate of PPCs.