Abstract. Background/Aim: Certain microRNAs (miRs) present in human plasma are candidate biomarkers for cardiovascular diseases, including acute myocardial infarction (AMI). We examined the expression of two cardiac-specific miRs (miR-208b and miR-499) MicroRNAs (miRs) are evolutionary small endogenous, noncoding, single-stranded RNAs involved in the regulation of gene expression at the post-transcriptional level (1). They possess an important role in multiple biological processes by binding to their target mRNAs and altering the protein expression of their candidate targets (2). Circulating miRs detected in serum or plasma, are actively secreted in macrovesicles or exosomes from different cell types (3), including cardiomyocytes. Elevated mRNA expression levels have been involved in numerous human pathologies including cardiovascular diseases (4).Acute myocardial infarction (AMI) is the acute necrosis of myocardial tissue due to persistent and severe ischemia, and remains a leading cause of morbidity and mortality worldwide (5). Accurate and rapid diagnosis is crucial for the clinical management and prognosis of AMI (6). Thus, exploration of new potential biomarkers that will contribute in this direction is particularly important. Although the circulating levels of cardiac troponin proteins are currently regarded as the most prominent biomarkers for the diagnosis of AMI, measurable amounts of troponins are not usually released from damaged myocardium earlier than 4-8 h after the onset of symptoms (6, 7). In contrast, the levels of circulating plasma miRs can be measured rapidly using realtime PCR, offering two main advantages over standard antibody-based assays: increased sensitivity and specificity. Several studies have already considered circulating cardiacspecific or -enriched miRs as new biomarkers for the early diagnosis of .In fact, the vast majority of these studies have been performed in Asian populations, while limited studies from European populations are also available (12). Consequently, better validation through larger studies is required for the establishment of miRs as biomarkers in clinical practice. Based on the elegant study of Huang et al. (13) who showed that miRNA expression levels exhibit population differences, and the recorded dysregulation of two specific myocardialderived miRNAs in AMI patients (14, 15), we decided to further investigate their expression in a Caucasian population. Specifically, the purpose of this study was to 313