Donation after circulatory death (DCD) is being used to increase the number of transplantable organs. The role and timing of steroids in DCD donation and ex-vivo lung perfusion (EVLP) has not been thoroughly investigated. In this study, we investigated the effect of steroids on warm-ischemic injury in a porcine model (n=6/group). Following cardiac arrest, grafts were left untouched in the donor (90 minutes warm ischemia). Graft function was assessed after 6 hours of EVLP. In MP-group, 500 mg methylprednisolone was given prior to cardiac arrest and during EVLP. In CONTR-group no steroids were added. Median lung compliance (13 ml/cmH2 0) was significantly better preserved in CONTR than in MP group (30.5 ml/cmH2 0). Also, median wet-to-dry-weight (6.11 vs 6.94) and CT-density (182.5 vs 352.9 g/L) were significantly better in MP-group than in CONTR-group, respectively. There was no difference in oxygenation and pulmonary vascular resistance. Perfusate cytokine analysis showed a significant reduction in IL-1β, IL-8, IFN-α, IL-10, TNF-α and IFN-γ in MP. Cytokines in bronchoalveolar lavage were not decreased except for IFN-gamma. We demonstrated that warm-ischemic injury in DCD donation can be attenuated by steroids when given prior to warm ischemia and during EVLP. Ethical context of donor preconditioning should be discussed further. This article is protected by copyright. All rights reserved.