Although eosinophilia (eosinophil count >0.60 × 10⁹/l), is a prothrombotic condition, little is known on the association between eosinophil count in blood and first-line coagulations tests, including fibrinogen, activated partial thromboplastin time (APTT), prothrombin time (PT) and platelet count. Cumulative results of APTT, PT, fibrinogen, platelet and eosinophil counts were retrieved from 6,944 outpatients >15 years old referred to our laboratory for routine blood testing over the previous 3 years. The median value and the percentage of patients with abnormal values of platelet count and fibrinogen but not APTT and PT, were significantly higher in patients with eosinophilia. This epidemiological association in a large subset of patients provides an additional potential mechanism to explain the link between eosinophilia and thrombosis and is consistent with the hypothesis that platelet count and fibrinogen might be worthwhile assessing in the presence of an abnormal eosinophil count.