Relevance. To investigate the prognostic value of the Charlson Comorbidity Index (CCI) and its components in assessing outcomes related to in-hospital and 18-month mortality and to determine additional prognostic value when incorporating them into the GRACE score among patients with acute myocardial infarction (MI). Material and methods. A prospective study enrolled 712 patients diagnosed with acute MI who underwent coronary angiography within 24 hours of hospitalization. Results and Discussion. Of the patients, 61 % were male, median age 65 (interquartile range [IQR] 56-74years). In-hospital and 18-month mortality rates were 5.1 % (n = 36) and 12.1 % (n = 86), respectively. Median GRACE, CCI scores were 117 (IQR: 98-141), and 4 (IQR: 3-6) respectively. Common comorbidities within the CCI components included previous MI (21.8 %), diabetes mellitus (21.1 %), chronic pulmonary disease (16.2 %), dementia (9.2 %), peptic ulcer disease (9.1 %), renal failure (8.6 %). Factors associated with in-hospital and 18-month mortality included chronic lung disease (odds ratio [OR] = 4.21 and 2.04, respectively) and renal failure (OR = 3.51 and 1.99, respectively) after adjusting for GRACE score. Dementia (OR 2.10; 95 % confidence interval [CI] 1.11-3.97) was a significant risk factor for 18-month mortality. CCI was associated with in-hospital and 18-month mortality (GRACE-adjusted OR 1.29, 95 % CI:1.07-1.57, p = 0.001 and 1.37, 95 % CI (1.20-1.57, p = 0.001, respectively). CCI demonstrated good predictive ability for in-hospital mortality (area under the ROC Curve [AUC]: 0.826) and modest performance for 18-month mortality (AUC: 0.797). Adding chronic lung disease, renal failure in the GRACE score significantly improved the predictive efficacy for in-hospital mortality, with an AUC of 0.932 (95 % CI: 0.905-0.959, p = 0.001). Including CCI in the GRACE score enhanced the prediction efficiency for 18-month mortality (AUC 0.819, 95 % CI: 0.768-0.871, p = 0.001). Conclusion. The CCI demonstrated moderate prognostic value in assessing in-hospital mortality among patients with acute MI and good predictive ability for long-term mortality. The CCI and its components (chronic lung disease, renal failure) added prognostic significance in addition to the GRACE score for predicting both short-term and long-term adverse outcomes. © Hoang T.H., Maiskov V.V., Merai I.A., Kobalava Z.D., 2024.