Background/aim: We compared the effects of volume-controlled equal ratio ventilation (VC-ERV) and volume-controlled conventional ratio ventilation (VC-CRV) on oxygenation, ventilation, respiratory mechanics, and hemodynamic status during mechanical ventilation with recruitment maneuver (RM) and positive end-expiratory pressure (PEEP) in patients undergoing laparoscopic sleeve gastrectomy. Materials and methods: A total of 111 patients scheduled for laparoscopic sleeve gastrectomy were randomized to ventilation with inspiratory to expiratory ratio of 1:1 (Group VC-ERV) or 1:2 (Group VC-CRV) following tracheal intubation. RM (40 cmH2O, 15 s) and PEEP (10 cmH2O) were administered to all patients. Arterial blood gas samples were taken and peak airway pressure (Ppeak), mean airway pressure (Pmean), dynamic compliance (Cdyn), mean arterial pressure, heart rate, SpO2, and EtCO2 were recorded at 4 time points. Postoperative respiratory complications were recorded. Results: Oxygenation, ventilation, Pmean levels, and hemodynamic variables were similar in both groups. VC-ERV significantly decreased Ppeak and increased Cdyn compared to VC-CRV at all time points of the operation (P < 0.05). No pulmonary complication was observed in any patients. Conclusion: VC-ERV provides significantly lower Ppeak and higher Cdyn with similar oxygenation, ventilation, hemodynamic parameters, and Pmean levels when compared to VC-CRV during mechanical ventilation with RM and PEEP in laparoscopic sleeve gastrectomy.