Purpose: The number of available donor lungs is still the limiting factor in lung transplantation. We have recently shown during ex-vivo lung evaluation that diluted surfactant lavage improved the graft function after gastric acid aspiration. In the present study we hypothesized that the same treatment in lungs injured by gastric acid aspiration may improve graft function in transplanted porcine lungs. Methods and Materials: Lung injury was induced by intratracheal instillation of 1 ml/kg Oroacid® by a flexible fiberoptic bronchoscope under direct vision into the left main bronchus and the animals were ventilated for 24 hours thereafter. Following harvest the donor lungs were stored at 4°C for 4 hours. In control group (n 4) left lung transplantation was performed without any treatment. In surfactant treated group (n 6) the recipients received intratracheal diluted surfactant (1 ml/kg) lavage just before reperfusion and ventilation. During 7 hours of reperfusion hemodynamic and ventilatory variables were recorded hourly. Bronchoalveolar lavage (BAL) was performed at the end of the experiment for bubble surfactometry and further analysis. Results: Surfactant lavage resulted in lower mean pulmonary artery pressure, lower airway pressure and better oxygenation compared to control group (p 0.001). BAL IL-6 level and neutrophil percentage at the end of the experiment was significantly higher in control compared to surfactant group (p 0.05). Minimal surface tension was significantly lower in surfactant group compared to controls (p 0.05). Conclusions: In this model diluted surfactant administration before reperfusion attenuates the injury and improves the graft function in lung transplantation.