Rationale: The "open lung" strategy aims at re-opening (recruitment) of non-aerated lung areas in patients with acute respiratory distress syndrome, avoiding tidal alveolar hyperinflation in the limited area of normally aerated tissue (baby lung). Objectives: We tested the hypothesis that recruited lung areas do not resume elastic properties of adjacent baby lung. Measurements and main results: Twenty-five anesthetized, mechanically ventilated pigs were studied. Four lung-healthy pigs served as controls while the remaining 21 were divided into 3 groups (n=7 each), in which lung injury was produced by surfactant lavage, lipopolysaccharide infusion, or hydrochloride inhalation. Computed tomography scans, respiratory mechanics and gas exchange parameters were recorded under three conditions: at baseline, during lung recruitment maneuver, and at end-expiration and end-inspiration when ventilating following an open lung protocol. During recruitment maneuver and open lung protocol the gas volume entering the insufficiently aerated compartment was 96 (75-117) and 48 (41-63) % (median – interquartile range) of the functional residual capacity measured before at zero end-expiratory pressure, respectively. Nonetheless, the volume of hyperinflated lung increased during both recruitment maneuver (by 1-28 % of total lung volume; P < 0.01) and open lung protocol ventilation at end-inspiration (by 1-15 % of total lung volume; P < 0.01). Regional elastance of recruited lung tissue was consistently higher than that of the baby lung regardless of the ARDS model (P <0.01). Conclusion: Alveolar recruitment is not protective against hyperinflation of the baby lung because lung parenchyma is inhomogeneous during ventilation following the open lung strategy.