A retrospective analysis of data collected in a previous study suggested that pre-conditioning levels of factor XII might have prognostic value in autologous graft recipients. In order to confirm whether pre-transplant factor XII (pFXII) levels could be correlated with outcome, seventy-six (35 autologous and 41 allogeneic) transplant recipients were prospectively evaluated. A significant direct relationship was found between pFXII levels and both overall and disease-free survival in the autologous grafts, but not in the allogeneic ones. Although the molecular mechanisms of this relationship still need to be clarified, these data seem to justify larger efforts to confirm whether factor XII (FXII) assay should be used in pre-transplant evaluation of patients.