Introduction: In the United States, Staphylococcus aureus (S.aureus) is considered one of the top five pathogens causing domestically acquired foodborne diseases and is responsible for an estimate of 241,000 illnesses per year. Foods that have been frequently implicated in Staphylococcal food-borne disease are meat, meat products, egg products, milk, dairy products, salads and bakery products. β-lactam antibiotics are routinely prescribed for treating S. aureus caused infections, but antibiotic resistance is increasing at an alarming rate. Aim: Detection of virulence factors and antibiotic resistance in S.aureus isolated from retail beef Materials and Methods : A total of 100 meat samples were collected from markets including Kharkhorin 28, Bars 4, Bayanzurkh 15, Huchit shonkhor 33, Denjiin myanga 4 and Bumbugur 16. S.aureus strains were determined on the basis of MNS 6308:2012 standard using Baird-Parker selective agar and confirmed by polymerase chain reaction (PCR) in retail beefs. Bacterial susceptibility to antimicrobial agents determined by the Kirby Bauer disk diffusion method. Results: Overall, 81% meat samples were contaminated with staphylococcal of which 54.3% were low, 28% were moderate, 11.1% were high and 6.1% were very high. PCR amplification of the thermostable nuclease-encoding nuc gene using the gene-specific primers and the chromosomal DNA preparation yielded a 270 bp amplicon, as expected and 35 (43.2%) confirmed as S. aureus. According to the findings of the current study, S.aureus strains isolated from the beef were high resistant (88.6% -97.1%) to antibiotics of penicillins group and low resistant (8.6%) to chloramphenicol. In total, 48.6% of isolates were multidrug resistant. Conclusion The contamination of staphylococcal was high in retail beef in Ulaanbaatar. Most S.aureus isolates exhibited resistance to a antibiotics of penicillin group. The half of the isolates were multidrug resistant and high virulence.