Global widespread extended-spectrum β-lactamase (ESBL)-producing Escherichia coli poses a significant threat in human healthcare and community settings. Chicken meat may be one of the critical transmission routes for those bacteria in the community. This study aimed to characterise 72 ESBL-producing E. coli isolated from 92 samples of chicken meat from 46 butcher shops in La Plata, Argentina. Antimicrobial susceptibility was evaluated using the disk diffusion method according to Clinical and Laboratory Standards Institute (CLSI) guidelines. The Whole Genome Sequencing (WGS) of the isolates were analysed on the Galaxy platform version 23.1. The ESBL resistance was mediated by blaCTX-M-2 (n=42), blaCTX-M-55 (n=14), blaCTX-M-14 (n=5), blaCTX-M-15 (n=5), blaCTX-M-65 (n=3), blaCTX-M-8, blaCTX-M-27, blaCTX-M-2/blaCTX-M-55 (n=1 of each one). Thirty-nine ESBL-producing E. coli harboured other plasmid-mediated genes that confer resistance to highest-priority critically important antimicrobial fosfomycin and ciprofloxacin. The gene fosL1 was principally associated with blaCTX-M-2 (n=15) and fosA3 exclusively to blaCTX-M-55 (n=7). The gene qnrB19 was associated with blaCTX-M-2 (n=13) and to blaCTX-M-55 (n=3) since qnrS1 was associated with blaCTX-M-15 (n=3) and to blaCTX-M-14 (n=1). Fourteen E. coli harbour genes conferred resistance to all three highest priority critically important antimicrobials (HPCIA): 3GC, fosfomycin and fluoroquinolones. All isolates were sensitive to carbapenems and colistin. ESBL-producing E. coli were multidrug-resistant (MDR), showing resistance to other groups of antimicrobial agents such as tetracyclines, amphenicols and aminoglycosides. Our results show a high circulation of ESBL-producing E. coli, resistant to other HPCIA that belong to CTX-M groups predominant in poultry and humans in Argentina. Future studies will be necessary to determine the origin of contamination of chicken meat within the production chain. The information obtained supports the promotion of measures that allow the implementation of strategies for the correct handling of food and prevent its transmission to humans.