Several studies have been published on the effect of bone-marrow stem cells on the left ventricle when acting on post- acute myocardial infarction remodeling. However, the results have been controversial.To carry out an echocardiographic analysis of the systolic function of patients with acute myocardial infarction after autologous mononuclear bone marrow cell transplantation (AMBMCT) as performed via the intracoronary and intravenous routes.This is an open-label, prospective, randomized study.patients admitted for ST-elevation acute myocardial infarction (MI) who had undergone mechanical or chemical reperfusion within 24 hours of the onset of symptoms and whose echocardiogram showed decreased segmental wall motion and fixed perfusion defect related to the culprit artery. Autologous bone marrow was aspirated from the posterior iliac crest under sedation and analgesia of the patients randomly assigned for the treatment group. After laboratory manipulation, intracoronary or intravenous injection of 100 x 106 mononuclear cells was performed. Echocardiography (Vivid 7) was used to assess ventricular function before and three and six months after cell infusion.A total of 30 patients were included, 14 in the arterial group (AG), 10 in the venous group (VG), and six in the control group (CG). No statistical difference was found between the groups for the echocardiographic parameters studied.Autologous mononuclear bone marrow cell transplantation did not improve the echocardiographic parameters of systolic function.