Purpose Mitochondrial danger associated molecular patterns (DAMPS) such as circulating mitochondrial DNA (mtDNA) is known to be released by injured cells following bone crush trauma and may induce acute lung injury in patients with systemic inflammatory response syndrome. However, it remains unclear if injured lungs also release mtDNA possibly contributing to primary graft dysfunction (PGD). Here we assess circulating mt DNA levels in lung recipients with or without PGD. Methods and Materials PGD (N=33) was graded immediately after arrival in the ICU in accordance with ISHLT criteria and plasma was isolated and purified for DNA using a Qiagen blood DNA isolation kit. Primers specific for cytochrome c oxidase, a single copy gene found only in the mitochondrial genome, were used to determine plasma mtDNA concentrations by comparison to a standard curve generated by purified mtDNA. Results Patients without PGD and healthy controls have comparable mtDNA levels and when compared to patients with PGD have significantly less mtDNA. [ figure 1 ] Notably, mtDNA plasma concentration also increases with PGD severity as PGD 2 patients have significantly higher mtDNA as compared to PGD 1 patients (p Conclusions Mitochondrial DAMPs are released in high amounts in patients with PGD suggesting a role in promoting inflammation. Quantitation of circulating mtDNA may be a sensitive non-invasive method to independently evaluate pulmonary tissue injury following lung transplantation.