Identification of heart transplant rejection currently rely on immunohistologic and immunohistochemistry. We aimed to identify specific sets of microRNAs (miRNAs) to characterize acute cellular (ACR), antibody-mediated (pAMR) and mixed (MR) rejections in monitoring formalinfixed paraffin-embedded (FFPE) endomyocardial biopsies (EMBs) in heart transplant (HTx) patients.