Staphylococcus aureus can cause a broad variety of infections, ranging from minor infections of the skin to serious necrotic pneumonia. Pathogenicity and high degree of multi-drug resistance are the characteristics of the methicillin-resistant Staphylococcus aureus ( MRSA ). The cause of resistance to methicillin and all other β-lactam antibiotics is the mecA gene, which is situated on a mobile genetic element, the staphylococcal cassette chromosome mec (SCCmec). Eight major variants of SCCmec, type Ⅰ to Ⅷ, are distinguished. This paper describes the structure and typing of SCCmec, its discovery, detection methods and distributiong are reviewed.