In the year 2000 a consensus document of the Joint European Society of Cardiology/American College of Cardiology Committee proposed new diagnostic criteria for acute myocardial infarction (MI), emphasizing the role of more sensitive and specific serologic biomarkers of myocardial necrosis. Although several criticisms soon followed this redefinition of acute MI, it was expected that these new criteria would substantially impact the clinical management and prognosis of patients with coronary artery disease. Important consequences on the health care system and government policies were supposed as well. However, 4 years later a substantial proportion of patients with acute MI are still diagnosed according to the old World Health Organization criteria, irrespective of the results of biomarker assays. This finding indicates that the redefinition of acute MI is far from being universally adopted. Thus, the reasons that hampered a widespread diffusion of such criteria, mainly a mixture of technical, logistic and cultural points, and the main, still controversial issues are discussed and commented on.