We aimed to evaluate the peculiarities of association of multimorbidity with cardiovascular risk in patients with acute coronary syndrome (ACS). Material and methods. The retrospective registry study included 1097 patients with ACS. The mean age of the patients of the entire sample was 62 (61—63) years. The in-hospital mortality within the studied group was 4.6%. The annual mortality from all the causes was 10.9% and the three-year mortality was 16.9%. The presence of at least 2 background pathologies: arterial hypertension, anemia, multivessel coronary artery disease or polyvascular disease, diabetes mellitus, stroke obesity or renal dysfunction was identified as the fact of multimorbidity, the proportion of which was 70.5%. Results. It was found out that the following factors were associated with multimorbidity: elderly age, female gender, high mortality risk by GRACE score, previous myocardial infarction, high Killip class of acute heart failure, reduction in the frequency of percutaneous coronary intervention (PCI) at the in-hospital stage and coronary artery bypass grafting (CABG) after discharge. The in-hospital and long-term mortality also increased significantly with the increase in the number of background diseases. Multivariate analysis allowed to identify that multimorbidity burdened the medium-term (annual) prognosis more than the in-hospital or tree-year prognosis. Conclusion. Multimorbidity has an unfavourable prognostic impact. Despite the association of multimorbidity with a decrease in the frequency of both PCI and CABG, the revascularization significantly improves the prognosis in this category of patients. The provided data allow to conclude not only about the need to increase the possibility of surgical revascularization execution, but also about the need for more effective medical examination of multimorbide patients.