Methicillin resistant Staphylococcus aureus (MRSA) pose an important problem in hospitals, nursing homes, and other health care settings. Serious infections due to these organisms currently necessitate use of non-β-lactam antibacterial therapy. For this reason, accurate detection of methicillin or oxacillin resistance among staphylococci is of great importance, consequently several techniques have been applied to this task, including agar plate screening, and disk diffusion tests. There are many lab methods for detection of methicillin resistance in S.aureus. The gold standard, for antimicrobial susceptibility testing has been the minimum inhibitory concentration (MIC). In recent years MIC methods has been replaced by molecular methods that detect mecA gene. However, the use of these assay is largely restricted to reference centers, and they are not currently available in most routine diagnostic labs. This book provides comparing several methods, including traditional and commercial methods for the detection of methicillin resistance in S. aureus with reference to the presence of mecA gene as the standard.