Background: A commensal bacterium has ability to cause a wide range of infections is Staphylococcus aureus device-related infections by regulator system called accessory gene regulator (agr). Methods: Identification S. aureus that isolated from urine clinical sample has been done according to the cultured on the mannitol salt agar and biochemical tests, then confirm the identification by amplification 16srRNA gene through conventional PCR and detection agr (I, II, III, IV) gene by multiplex PCR then expression of agr gene with antibiotic and without antibiotic by real time (qPCR). Result: VThirty isolates of S. aureus diagnosed and (76,70%) percentage of this isolates resistance to amoxicillin and found all this isolates have agr gene that related with antibiotic resistance.