Excessive amount of extravascular lung water (EVLW) resulting from increased permeability of alveolo-capillary membrane is a pathophysiological hallmark of acute respiratory distress syndrome (ARDS). Increased EVLW produces hypoxemia by interference with gas exchange. During shock resuscitation, in disorders in which microvascular endothelial integrity is impaired, large volumes of intravenous fluids needed to restore tissue perfusion may also be associated with the risk of increased accumulation of EVLW. The presented paper briefly reviews the mechanisms involved in lung edema formation and describes current options to measure EVLW. In addition, it discusses clinical implications of EVLW measurement in intensive care setting with particular focus on transpulmonary indicator dilution technique.