Staphylococcus aureus (S. aureus) is a clinically significant pathogen widely distributed in food production environments. Its ability to form biofilms on food contact surfaces enhances 50 environmental persistence, increases antibiotic resistance 10–1500-fold, and poses serious challenges for food safety and public health. In Mongolia, data on the biofilm-forming ability of S. aureus in meat processing and retail environments are limited. A cross-sectional study was conducted on 437 samples collected from meat supply and retail sites, including raw meat, aprons, counters, trolleys, and workers’ hands. Isolation and confirmation of S. aureus were performed using MNS 6308:2012 and ISO 6888-1:2021 standards, followed by PCR amplification of the species-specific nucA gene (270 bp). Biofilm formation was evaluated using the microtiter plate assay with 0.5% glucose supplemented tryptic soy broth and optical density at 490 nm, and confirmed by scanning electron microscopy (SEM). Statistical analyses were performed using chi-square tests with p< 0.05 considered significant. Of the 437 samples, 14.2% (62/437) were contaminated with S. aureus. Contamination was higher in retail markets (25.9%) than supply sites (9.3%). Among isolates, 40.3% exhibited biofilm-forming ability: 29.0% weak, 9.7% moderate, and 1.6% strong. Biofilm formation did not significantly differ by sampling site or sample type (p>0.05). SEM imaging revealed distinct biofilm architectures with polysaccharide matrices at 80,000× magnification. A considerable proportion of S. aureus isolates from meat processing and retail environments exhibited biofilm forming ability, posing a potential risk for cross-contamination and persistent foodborne transmission. Strengthened hygiene and sanitation measures are essential to control biofilm-associated S. aureus contamination in Mongolia’s meat production and supply chain.