Primary graft dysfunction (PGD) causes significant mortality and morbidity after lung transplantation. The objectives of the study were to describe the clinical and histological sequelae of PGD.Histology of all patients receiving single-lung transplantation 1999-2004 (n=181) was reviewed. PGD was defined as diffuse radiological infiltration of the lung allograft occurring within the first 72h postoperatively.One patient died intra-operatively. PGD was recorded in 63% (n=113) of 180 consecutive transplant recipients. Patients with PGD had a worse 90-day postoperative mortality (14% versus 3%, p=0.03) and 3-year survival (55% versus 77%, p=0.003). Freedom from bronchiolitis obliterans syndrome was similar in both groups. The maximal FEV(1) was significantly lower in patients with PGD, median 54% (quartiles 48-61%) predicted; compared to patients without PGD, median 59% (quartiles 54-69%) predicted (p=0.003). There was a significant linear trend in the decline of maximal FEV(1) with the presence and increasing severity of radiographic infiltrate (p=0.004). During follow-up, patients with PGD were more likely to demonstrate diffuse alveolar damage or bronchiolitis obliterans organizing pneumonia (p=0.009 and p=0.01, respectively). Histological findings of diffuse alveolar damage correlated closely with extent of radiological infiltration (p<0.0001).Transplant recipient survival, lung function, and histological findings of diffuse alveolar damage appear to be closely correlated with the appearance and severity of PGD.