Methicillin-resistant Staphylococcus aureus (MRSA) is a typical pathogen of nosocomial infection, and has recently emerged as an important community-acquired pathogen. MRSA is notorious as a multidrug- resistant organism. Its resistance to all β-lactams is mediated by PBP2a which is encoded by mecA, and it is also resistant to many antimicrobials of other classes due to frequently co-carrying resistance genes, which accounts for becoming a clinical and laboratory issue. This article reviews the microbiological characteristics, surveillance methods, and molecular epidemiology of MRSA. (Korean J Clin Microbiol 2010;13:1-6)