Objective -Comparative analysis of the in-hospital results after primary implantation of stents or coronary balloon angioplasty in patients with acute myocardial infarction (MI). Methods -CENIC (National Center of Cardiovascular Interventions) gathered data on 3,924 patients undergoing coronary angioplasty (in the primary form, without the previous use of thrombolytic agents) in the first 24 hours after a MI, during the period of 1996 (6.3% vs. 4.5%, p=0.01), anterior MI and stent implantation in left descending artery (55% vs. 48% vs. p=0.009), and saphenous vein bypass grafts (3.3% vs. 1.9%). the procedure was more succesful in the group of stents (97% vs. 84%, p=0.001) and reinfarction rate (2.5 vs. 4%, p=0.002). The need for emergency revascularization was similar (1% vs. 1.1%, NS). Total in-hospital mortality was lower in stent group (3.4% vs. 7. 2%, p=0.0001) Primary coronary angioplasty is one of the preferred methods of myocardial reperfusion performed without previous use of thrombolytic agents for the treatment of acute myocardial infarction [1][2][3][4][5] . It provides high levels of immediate arterial permeability with TIMI 3 optimal coronary flow 6 . When available, it is comprehensive and offers a significant reduction in the occurrence of major immediate events, such as reinfarction, stroke, and death 3,5 .Results of randomized studies 7,8 , registries 9 , and consecutive series 10 , however, with the application of primary coronary angioplasty in acute myocardial infarction showed loss of immediate and late results in some subgroups of patients. In the in-hospital phase, the number of recurrent ischemias and reinfarctions was higher when suboptimal results were present (residual stenosis >30% and significant coronary dissection); at 6 months, restenosis and reocclusion of the vessel initially treated were as high as 45% and, in 25% of the cases, new myocardial revascularization procedures were performed , 9,10 .Coronary stent implantation in acute myocardial infarction is a recent therapeutical option aiming to optimize immediate and late results [11][12][13][14][15][16][17] , based on evidence observed in elective patients 18,19 .Our aim was to assess the in-hospital results of two techniques of percutaneous coronary revascularization in the acute phase of myocardial infarction: primary coronary stent implantation and conventional primary coronary balloon angioplasty. These two techniques are part of the national registry of procedures, CENIC (National Center of Cardiovascular Interventions), which belongs to the Sociedade Brasileira de Hemodinâmica e Cardiologia Intervencionista -SBHCI