Many years after its initial description, Acute Respiratory Distress Syndrome (ARDS) has been acknowledged as an extremely heterogeneous disease with low lung volumes. This lung with reduced aeration capacity ("baby lung") is the one that accounts for Ventilation Induced Lung Injury (VILI). The evidence shows that direct mechanical injury is the main responsible of VILI and its remote biological amplification. The cyclic transpulmonary pressures that exceed lung inflation capacity can damage the epithelium-alveolar barrier, especially in association with insufficient PEEP to keep the mechanically unstable alveolar units open. At present time, therapies that can interfere and modulate efficiently the trigger of biological events leading to VILI have not been developed. Thus, the only therapy available is the cautious use of mechanical ventilation (MV). The wise implementation of MV strategy will result in a lower stress and strain of lung parenchyma, with reduction in its biological impact. Hence, the main message of this review is that the way we ventilate our patients is decisive in their outcome and we must try to minimize VILI from the moment we start to ventilate our patient. In the present communication, we attempt to review basic concepts, anatomic-functional aspects of this mechanical phenomenon and its biological consequences. Clinical interventions that allow to attenuate the impact of ventilatory support are described