Abstract Objective ACE Insertion/deletion (I/D) polymorphism has been reported to be associated with various cardiovascular conditions, however its impact in patients with AHF remains controversial. This study aimed to analyze ACE I/D distribution, rate of acute heart failure (AHF) and survival in ST segment elevation myocardial infarction (STEMI) patients. Methods Genomic DNA from 245 STEMI patients and 87 healthy control subjects were analyzed by single polymerase chain reaction method. Based on the ACE I/D genotype STEMI patients were divided with AHF/no AHF, and then - for preserved/reduced ≤40% left ventricle (LV) ejection fraction (EF) to investigate the frequency of the mutant allele D. Results ACE gene polymorphism analyses revealed that D allele had been found more often in STEMI patients than in controls (84.1 vs. 72.4%). The frequency of II, ID, and DD genotypes in STEMI patients was 27.6%, 52.9% and 19.5% compared to 15.9%, 54.3% and 29.8%, respectively in controls with a significant difference in mutant homozygous genotype. Distribution of I/D ACE gene variants among AHF cases vs no AHF, showed similar frequency of II allele (15.8 vs 13.5%), ID allele (54.9 vs 52.8%) and DD allele (29.3 vs 33.7% respectively). In patients with preserved EF there was not statistical significance among different alleles with and without AHF. However, ACE DD polymorphism has been found in AHF patients with reduced EF significantly more often (50.0 vs 30.5%; p<0.05) in compare to AHF patients with preserved EF. Finally, cardiovascular death among all STEMI patients during 3-year follow up was more frequent in patients with DD allele (17.7% vs 5.7% with II and vs 9.9% with ID allele). Conclusion Presented results confirmed ACE DD polymorphism to be associated with higher rate of cardiovascular death and presence of AHF with reduced LV EF in STEMI patients. Future studies are needed to evaluate importance of ACE DD polymorphism in order to find optimal treatment strategies and to prevent negative outcomes in those patients. Funding Acknowledgement Type of funding sources: None.