Acute myocardial infarction (AMI) is a severe cardiovascular disease.This study aimed to identify crucial microRNAs (miRNAs) and mRNAs in AMI by establishing a miRNA-mRNA network.The microarray datasets GSE31568,GSE148153,and GSE66360 were downloaded from the Gene Expression Omnibus (GEO) database.We identified differentially expressed miRNAs (DE-miRNAs) and mRNAs (DE-mRNAs) in AMI samples compared with normal control samples.The consistently changing miRNAs in both GSE31568 and GSE148153 datasets were selected as candidate DE-miRNAs.The interactions between the candidate DE-miRNAs and DE-mRNAs were analyzed,and a miRNA-mRNA network and a protein-protein interaction network were constructed,along with functional enrichment and pathway analyses.A total of 209 DE-miRNAs in the GSE31568 dataset,857 DE-miRNAs in the GSE148153 dataset,and 351 DE-mRNAs in the GSE66360 dataset were identified.Eighteen candidate DE-miRNAs were selected from both the GSE31568 and GSE148153 datasets.Furthermore,miR-646,miR-127-5p,miR-509-5p,miR-509-3-5p,and miR-767-5p were shown to have a higher degree in the miRNA-mRNA network.THBS-1 as well as FOS was a hub gene in the miRNA-mRNA network and the protein-protein interaction (PPI) network,respectively.CDKN1A was important in both miRNA-mRNA network and PPI network.We established a miRNA-mRNA network in AMI and identified five miRNAs and three genes,which might be used as biomarkers and potential therapeutic targets for patients with AMI.