Patients with ST-elevation myocardial infarction (STEMI) exhibit pro-thrombotic and pro-inflammatory states. Markers of enhanced platelet reactivity and inflammation are predictive of adverse outcome. However, the relationship between these biomarkers, and their combined usefulness for risk stratification, is not clear. In a prospective study of 541 patients presenting with STEMI, blood samples were taken on arrival to measure high-sensitivity C-reactive protein (hs-CRP), neutrophil/lymphocyte ratio (NLR) and platelet reactivity using the point-of-care Global Thrombosis Test. These biomarkers, alone and in combination, were related to the occurrence of major adverse cardiovascular events (MACE, defined as composite of cardiovascular death, myocardial infarction and cerebrovascular accident) at 30 days and 12 months. Platelet reactivity and hs-CRP, but not NLR, were weakly predictive of MACE at 30 days and 12 months. The combination of enhanced platelet reactivity and raised hs-CRP was strongly predictive of MACE at 30 days (hazard ratio [HR] 3.46 [95% confidence interval [CI] 1.81-6.62],  < 0.001) and 12 months (HR 3.46 [95% CI 1.81-6.63],  < 0.001). Combination of all three biomarkers (NLR, hs-CRP and platelet reactivity) provided the best prediction of MACE at 30 days (HR 3.73 [95% CI 1.69-8.27],  < 0.001) and 12 months (HR 3.85 [95% CI 1.72-8.60],  < 0.001), and improved the prediction of MACE when added to Thrombolysis In Myocardial Infarction score (net reclassification index 0.296,  < 0.001). A combination of three easy to measure biomarkers on arrival, namely hs-CRP, NLR and platelet reactivity, can help identify STEMI patients at high risk of recurrent adverse events over the subsequent year.