Background: We assessed the predictive value of estimated whole blood viscosity (WBV) in-hospital and long-term cardiovascular outcomes in patients with ST-elevation myocardial infarction (STEMI). Materials & methods: One thousand eight hundred and thirty-five STEMI patients were followed up for median 34.6 months. WBV was calculated consistent with the de Simone's formula. Results: In-hospital and long-term major adverse cardiovascular events (MACE) demonstrated an incremental trend in ascending order of WBV tertiles at low and high shear rate. Kaplan-Meier analysis showed a higher occurrence of long-term MACE in third WBV tertiles compared with other tertiles. Conclusion: WBV seems to be a feasible prognostic indicator of short-and long-term cardiovascular adverse events in patients with STEMI. As an easily available parameter, WBV may be utilized in identifying high-risk patients for subsequent MACE.