The authors researched into the possibility of autologous bone marrow stem cell (MSC) application in patients with acute myocardial infarction (AMI). 10 patients with AMI received cell therapy after giving an informed consent. ECG and EchoCG revealed myocardial infarction (MI) in the basin of the anterior interventricular branch (AIB) of the left coronary artery (LCA) in 4 patients, in the basin of the circumflex branch (CB) of the LCA--in 3 patients, and in the basin of the right coronary artery (RCA)--in 3 patients. Patients older than 70, patients with acute heart failure and those who developed AMI more than 48 hours ago, were excluded from the study. All the patients were male, aged 56.3 +/- 5.2 years, mean time from pain onset to the performance of myocardial revascularization was 11.4 +/- 7.2 hours. Marrow mononuclear fraction was introduced into the infarction-related artery on the 5th-7th day after primary angioplasty and stenting. Marrow sampling and cell material introduction did not cause any complications. All the patients were re-studied 1 month after the MSC transplantation. All the patients' condition improved; no complications or side effects of the interventions were observed. Left ventricle ejection fraction increased from 42.9% to 51.4%; the average number of asynergic segments was 5.3 +/- 0.7 before the intervention and decreased to 2.6 +/- 0.7 (p < 0.01) afterwards. Systolic velocity before the intervention was 2.5 cm/sec, and after the procedure it increased to 4.6 cm/sec in the segments submitted to isolated revascularization and to 6.1 cm/sec--in segments where the intervention was accompanied by the introduction of MSC (p < 0.01). Contrast EchoCG demonstrated an increase of myocardial perfusion in the area of cell therapy. The chief results of the study are as follows: 1) autologous MSC transplantation in patients with acute coronary syndrome is a safe and well-tolerated procedure; 2) myocardial revascularization in combination with MSC introduction in AMI area improves total and local contractile myocardial function and normalizes diastolic filling process in the LV; 3) cell therapy improves the myocardial perfusion.