OBJECTIVES Ex vivo lung perfusion (EVLP) is not only used to assess marginal donor lungs but is also used as a platform to deliver therapeutic agents outside the body. We previously showed the beneficial effects of trimetazidine (TMZ) on ischaemia reperfusion (IR) injury in a rat model. This study evaluated the effects of TMZ in a pig EVLP transplant model. METHODS Pig lungs were retrieved and stored for 24 h at 4°C, followed by 4 h of EVLP. Allografts were randomly allocated to 2 groups ( n = 5 each). TMZ (5 mg/kg) was added to the prime solution prior to EVLP. After EVLP, left lungs were transplanted and recipients were observed for 4 h. Allograft gas exchange function and lung mechanics were recorded hourly throughout reperfusion. Microscopic lung injury and inflammatory and biochemical parameters were assessed. RESULTS There was a trend towards better oxygenation during EVLP in the TMZ group ( P = 0.06). After transplantation, pulmonary gas exchange was significantly better during the 4-h reperfusion period and after isolation of the allografts for 10 min ( P < 0.05). Tissue thiobarbituric acid levels, myeloperoxidase activity and protein concentrations in bronchoalveolar lavage samples were significantly lower in the TMZ group at the end of EVLP ( P < 0.05). CONCLUSIONS Ex vivo treatment of donor lungs with TMZ significantly improved immediate post-transplant lung function. Further studies are warranted to understand the effect of this strategy on long-term lung function.