Background and objectives: Adrenomedullin (AM), a peptide involved in cardiovascular homeostasis, is believed to protect cardiac functions by increasing local blood flows, attenuating the progression of vascular damage and remodelling. This work was performed to investigate whether an increase in circulating AM might be related to myocardial infarction, and whether cardiovascular morbidity can be predicted by AM. Methods: heart rate and systemic blood pressure were measured together with plasma adrenomedullin levels and cardiac enzyems in sixty patients with acute coronary syndrome as well as in 20 healthy subjects matched for age, gender served as control group. Systolic cardiac functions were assessed, using Doppler echocardiography. Results: Plasma adrenomedullin levels were significantly higher in myocardial infarction group compared to control. Subjects were similar concerning mean age, heart rate and blood pressure. Cardiac systolic functions were impaired in myocardial infarction patients compared to controls. In a simple correlation analysis, plasma adrenomedullin levels were negatively correlated with left ventricular ejection fraction. Patients with high plasma AM levels had higher morbidity than those with low plasma AM levels. AM levels were higher in patients receiving thrombolytic therapy than other groups. Conclusion: myocardial infarction patients present with increased adrenomedullin levels that correlate with cardiac systolic dysfunction. These levels may provide a possible index of these conditions in myocardial infarction patients with concomitant cardiovascular disease.