Introduction – Cardiac transplantation has become the standard treatment for end stage heart disease, yet allograft rejection has limited survival rates to approximately ten years. While the role of the T- Lymphocyte in this process has been elucidated, there is growing evidence to support the contribution of the neutrophil in the rejection process. Based on previous studies by our own group, we hypothesized that the extent of neutrophil infiltration varies individually and that this neutrophil migratory potential correlates with subsequent rejection grades. The aims of this study were to determine variations in neutrophil adhesion molecule expression following stimulation and that evaluation of this response pre-operatively could predict subsequent rejection grades in heart transplantation. Materials and Methods – Whole blood was obtained from 11 patients prior to cardiac transplantation and stimulated with PMA (1ng/ml) for 20 minutes, LPS (1ug/ml) and fMLP (1ng/ml) for 60 minutes and subsequently stained with antibodies to CD11b, CD62L and PSGL-1 and surface expression determined by flow cytometry. Intra – operative whole blood samples were also taken during the surgical procedure and stained as above. Endomyocardial biopsies were taken on day 10 post transplant and rejection grades pathologically assessed. Statistical analysis was carried out using the Pearson Correlation test. Results – PMA, LPS and fMLP all stimulated differential expression of CD11b, CD62L and PSGL-1 with individual variation in their expression. fMLP stimulated CD11b expression pre-operatively correlated with the surgical CD11b response (P = 0.013). In the transplant patients, pre-operative CD11b response to LPS positively correlated with rejection grades on day 10 post surgery. (P = 0.022) Conclusion – Individuals differ in their basal and stimulated expression of CD11b, CD62L and PSGL-1. Artificially stimulating neutrophils can simulate neutrophil responses to surgical trauma. In transplant patients stimulated expression of CD11b could predict the severity of rejection. These results not only implicate the neutrophil as a contributor to allograft rejection, but also advocate the possibility of using pre-operative neutrophil migratory potential as a marker of endomyocardial biopsy rejection grade. This would allow for earlier modulation of immunosuppressive therapy at the time of transplantation, before endomyocardial biopsy grades.