Background. Acute decompensated heart failure (ADHF) is one of the most common cause for hospital admission in elderly patients. It is well known type 2 diabetes mellitus (T2DM) is one of the factors that worsens the prognosis of patients hospitalized with ADHF. The impact of T2DM on the further course of the disease after discharge requires study. Aim — to assess the impact of T2DM on five-year survival for ADHF patients. Material and methods. The study of the hospital register of acute decompensated heart failure (ADHF) was performed. The register contains 735 consecutively admitted ADHF patients for 2010—2011. Median follow-up was 1790 days. Results. 254 patients (35% of the cohort) suffered from T2DM. Diabetic patients’ average age was 70±9 years, nondiabetic ADHF patients age was 68±12 (p=0.04, Student’s t-test). Women accounted for 66% of the T2DM patients vs. 45% of nondiabetic ADHF patients (p<0.001 Pearson Chi-square). In the T2DM group atrial fibrillation was less common (37% vs. 51%; p<0.001, Pearson Chi-square), chronic obstructive pulmonary disease was also less common (23% vs. 34%; p=0,003, Pearson Chi-square). T2DM patients were characterized by more frequent hypertension (89% vs 79%; p<0.001, Pearson Chi-square) and obesity (50% vs. 27%; p<0.001, Pearson Chi-square). The initial creatinine level was higher in the T2DM group (114±67 vs. 102±51 mmol/l; p=0.009, Student’s t-test). Insulin was administered to 34% of diabetic patients. The other T2DM patients received oral hypoglycemic therapy. Hospital ADHF mortality rate in T2DM group was 10.2% (26 patients) versus 6.0% (29 patients); p=0.04 (Pearson Chi-square). Multivariate analysis was performed: the presence of type 2 diabetes increased the risk of death during the index hospitalization due to ADHF by 2.0 times (OR 2.0, 95% CI 1.1—3.6; p=0.03, logistic regression). Re-hospitalization due to ADHF over the next 18 months was higher in T2DM patients: 22% (51 cases) vs. 16% (74 cases); p=0.06 (Pearson Chi-square). 18-month T2DM patients survival rate was 0.69 vs. 0.77 (p=0.03, Kaplan—Meier). The presence of T2DM increased the risk of death within 18 months 1.4-fold (p=0.04, Cox regression). 165 (65%) T2DM patients died over 5 years vs. 278 (58%) nondiabetic patients, the survival curves differed significantly (p=0.03, Kaplan—Meier). In the Cox model, the presence of type 2 diabetes increased the risk of death within 5 years 1.2-fold (p=0.03). The study of the causes of death (total 443 cases) revealed that in T2DM group 52% of outcomes happened due to progression of heart failure. In the absence of diabetes, only 41% of outcomes related to the progression of heart failure (p=0.03, Pearson Chi-square). Conclusions. Diabetes can be considered frequent concomitant state in acute decompensated heart failure patients (up to 35% of cases). Diabetes increased demand of re-hospitalization due to heart failure over 18 months. T2DM is an independent risk factor for death during the index hospitalization and over the next 18 months and 5 years (increasing the risk of death 1.2—2.0-fold)