Objective. To evaluate the effectiveness of implantable cardioverter defibrillators (ICDs) in prevention of sudden cardiac death (SCD) and their impact on overall mortality, to identify predictors of justified ICD shocks and to clarify risk stratification in patients with dilated cardiomyopathy (DCMP). Material and methods. There were 293 patients with DCM syndrome (200 men). Mean age of patients was 46.2±12.8 years. Inclusion criteria were left ventricular (LV) end-diastolic dimension (EDD) over 5.5 cm and LV ejection fraction (EF) less than 50%. Patients with coronary artery stenoses over 50% were excluded. ICD/CRT-Ds were implanted in 79 (46/33) patients. The follow-up period was 26 months [22, 29]. Results. In patients with ICD, incidence of SCD was 1.6%, mortality — 22.8%, combined endpoint «death+transplantation» — 31.6%. In patients without ICD, these values were 2.8, 15.0 and 16.4%, respectively. There were no significant differences. There were significant differences in combined endpoint «sudden cardiac death + shock» (25.3% in patients with ICD vs 2.8% in patients without ICD, p<0.005). Justified shocks were noted in 25.3% of cases. Primary DCM syndrome (combined with myocarditis / isolated — 70%/25%) was established in 95% of patients with shocks compared with 49% (32%/17%) of patients without shocks (p<0.01). Stable ventricular tachycardia (VT) before ICD implantation was more common in patients with shocks (30.0 vs 5.1%, p=0.08), incidence of unstable VT was also somewhat higher (80.0 vs 74.5%). Low LVEF was not a risk factor of VT or ventricular fibrillation, but high negative predictive value of reduced QRS voltage was confirmed. Conclusion. In patients with DCM syndrome, ICD/CRT-D implantation is effective method for prevention of SCD. It is advisable to use primary/genetic nature of DCM as an independent criterion for selection of patients for ICD/CRT-D implantation. Additional predictors of justified shocks are stable VT and low QRS voltage.