Objectives: Myocardial infarction (MI) may be classified as ST elevation MI (STEMI) or non-ST elevation MI (NSTEMI). Procoagulants such as plasminogen activator inhibitor-1 (PAI-1) as well as markers of inflammation such as C-reactive protein (CRP), serum amyloid A (SAA) and interleukin-6 (IL-6) are elevated in acute coronary syndromes. However, no study has examined whether levels of these markers differ in patients with STEMI as opposed to NSTEMI. We sought to determine whether there are differences in plasma levels of PAI-1, CRP, SAA or IL-6 in patients with STEMI compared to patients with NSTEMI. Methods: Seventy-six consecutive patients presenting with acute MI (37 with STEMI and 39 with NSTEMI) were prospectively enrolled. Blood samples were obtained from patients within 6 h from presentation and plasma PAI-1, CRP, IL-6 and SAA concentrations were measured. Results: Plasma levels of PAI-1 were significantly higher in patients with STEMI compared to NSTEMI: 85.7 ± 5 vs. 61.3 ± 5 ng/ml (p < 0.001), while CRP, SAA and IL-6 levels were not significantly different between STEMI and NSTEMI patients. Conclusions: Higher plasma PAI-1 levels in STEMI patients may contribute to the predilection of these patients to occlusive thrombi and STEMI.