This study sought to investigate the predictive value of whole blood viscosity (WBV) to identify high-risk patients who will develop an apical thrombus during the acute phase of anterior transmural infarction. Consecutive 1726 patients with first acute anterior myocardial infarction were evaluated. WBV was calculated according to the Simone's formula. Patients with an apical thrombus had prolonged pain to balloon time, higher rate of post-PCI thrombolysis in myocardial infarction flow ≤ 1 and significantly higher mean WBV values at both shear rates than those without an apical thrombus. WBV values at both shear rates were found to be significant and independent predictors for early LV apical thrombus formation complicating a first-ever anterior wall myocardial infarction.