Prophylactic parenteral antibiotics have contributed to the present low rate of surgical site infections following hip and knee arthroplasty. Over the past decade, there has been a change in the pattern of methicillin-resistant Staphylococcus aureus infections from hospital-acquired to community-acquired. The findings of recent studies on screening programs to identify carriers of methicillin-resistant Staphylococcus aureus have been equivocal, with some studies showing that such programs reduce the rate of infections and others showing no effect on infection rates. Hospitals with antibiogram data that reveal high Staphylococcus resistance should consider use of vancomycin as a prophylactic antibiotic.