The incidence of isolation of Staphylococcus aureus strains resistant to methicillin is increasing in England and other European countries, whereas there have been only isolated reports of resistance in the United States. We thought this contrast might be related to the use of special sensitive screening techniques (i.e., incubation at 30 C, prolonged incubation, use of 5% sodium chloride-agar medium, and use of a large inoculum) in these other countries. A survey was undertaken in a hospital in Philadelphia to detect methicillin-resistant S. aureus . In spite of using large inocula, 5% sodium chloride-agar medium, and prolonged incubation at 30 C, no strains of S. aureus resistant to methicillin were found.