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Introduction: Staphylococcus aureus (S. aureus) is a bacterium found on the skin and hair of people and animals. S. aureus could product some extracellular protein. Materials and methods: One hundred and fifty S. aureus isolates that were collected from different resources were screened for the mecA, tst-1, eta and etb genes by PCR. 50 isolates were selected from human staphylococcal isolates and 100 from animal staphylococcal isolates. Results: Ten out of the 50 human S. aureus isolates and 5 out of 50 S. aureus isolates from milk cow were just positive for mecA but none of the poultry S. aureus isolates were positive for mecA. All of the isolates were negative for the eta, etb, tst-1. Conclusion: The results in this study indicate that the prevalence of mecA in human staphylococcal isolates is higher than prevalence of this gene in poultry staphylococcal isolates in Ilam- Iran but for the other genes there is no difference. Detection of mecA in cow milk could be a pose for public health hazards.