Background: The revised World Health Organization (WHO) diagnostic criteria for the diagnosis of polycythemia vera (PV) and essential thrombocythemia (ET) now implement detection of JAK2 V617F mutation. Patients with these myeloproliferative neoplasms (MPNs) are at increased risk towards atherothrombotic complications. Therefore, diagnosis of PV or ET is of high clinical relevance, especially in patients already affected by coronary artery disease (CAD). However, the prevalence of the JAK2 V617F mutation in coronary patients is unknown. The aim of this study was to determine JAK2 V617F mutational status and its association to blood cell values in a large cohort of coronary patients. Methods: The present study included a total of 1,599 patients undergoing coronary angiography for the evaluation of suspected or established stable CAD. Genomic DNA was extracted from whole blood and JAK2 V617F mutation analysis was carried out by allele-specific real-time PCR. In JAK2 V617F mutation positive patients, quantification of the mutation was performed using a commercially available PCR assay. Results: Twenty-two samples of 1,593 successfully genotyped subjects were found positive for the JAK2 V617F mutation (1.4%). Mean blood cell values of patients with JAK2 V617F percentage below 1% (n=4) did not differ from those without detectable JAK2 mutation. Individuals with JAK2 V617F percentage >= 1% (n=18) had significantly higher white blood cell (p=0.018) and platelet counts (p=0.043), but significantly lower haemoglobin levels (p=0.037) compared to patients without JAK2 mutation, although blood cell values of most positive subjects were within the normal range. Only three of the JAK2 V617F positive patients had blood test results indicative for MPNs, in particular increased platelet counts reaching threshold values recommended by the WHO for the diagnosis of ET. Conclusions: Our data demonstrate that the JAK2 V617F mutation is much more common than diagnosis of myeloproliferative diseases in coronary patients. However, our data suggest that JAK2 V617F positivity (>= 1%) is associated with moderately disturbed blood cell counts but may predict future full blood cell abnormalities. Prospective studies are warranted to verify this hypothesis.