Methods to detect resistance to methicillin in Staphylococcus epidermidis were studied in order to find a rapid screening test suitable for routine use. One hundred and forty-nine clinical isolates, 16 isolates from skin of healthy people and two reference strains were studied. Hypersecretion of β-lactamase as a cause of methicillin resistance was eliminated in the strains studied. Tube and microtitre breakpoint, agar breakpoint and disc diffusion methods were compared. The breakpoint for methicillin resistance used was 16 mg/L in broth and 10 mg/L in agar. The discs used contained 1 and 5 μg oxacillin and 5 and 10 μg methicillin. Turbidimetric measurements in broth during incubation were carried out using the Bioscreen analysing system. The skin strains were found to be susceptible in all tests. Using an inoculum of 107cfu/mL 111/149 clinical isolates were classified as resistant after incubation for 24 h at 35°C using the tube and microtitre breakpoint tests, incubation for 72 h did not increase this rate. When an inoculum of 105 cfu/mL was used 73% of these strains were identified within 24 h and all within 72 h with the tube breakpoint test. Using the microtitre breakpoint test, with an inoculum of 105 cfu/mL or lower, all resistant strains were not detected within 48 h. All agar breakpoint tests required 48 h incubation for reliable results. Only the 1 μg oxacillin disc always separated strains found to be resistant or susceptible in the tube breakpoint test. The zone of inhibition was dearly readable after 16 h of incubation at 35°C.