The incidence of nosocomial infections caused by oxacillin (methicillin) resistant CoNS has increased in many countries worldwide. Detection of methicillin resistance is problematic as the mecA gene may not be expressed by all cells, a fact resulting in the phenomenon of heterogenous resistance. To overcome this problem, several phenotypic and genotypic methods have been used to detect methicillin resistance. Identification of the mecA gene is the most reliable method of detecting MRCoNS however, not all laboratories can include molecular biology techniques in their routine practice. Thus, it is essential that phenotypic techniques able to detect methicillin-resistant isolates in a rapid and accurate manner are made available, in order to ensure correct antibiotic treatment and to avoid spread of MRCoNS in the hospital environment.