The presence or absence of the mecA gene, the determinant of resistance to all beta-lactam antibiotics, was examined in clinical isolates of Staphylococcus aureus by multiplex polymerase chain reaction (MPCR). Two pairs of primers were used, which yielded two specific products; a 280-bp nuc- based PCR fragment (amplification product of the nuc gene encoding specific Staphylococcus aureus nuclease) and a 533-bp mecA-based PCR fragment (amplification product of the mecA gene). The MPCR system was designed to be incorporated into the work flow in clinical diagnostic laboratories as a routine analysis.