Methicillin-resistant Staphylococcus aureus (MRSA) isolated in our hospital between 1986 and 1989 were mainly examined for their susceptibility to various antibiotics and coagulase types. The isolation frequency of MRSA among S. aureus isolated from clinical specimens has been steadily increasing; 37.8% in 1986, 49.8% in 1987, 60.6% in 1988 and 63.2% in 1989. This trend was particularly noticeable in the specimens associated with the respiratory tracts. The isolation rate of MRSA in the surgery and pediatrics wards was higher than that in the internal medicine ward. More than 80% of MRSA were coagulase type II, which were multi-resistant to penicillins, cephems, aminoglycosides and macrolides, and sensitive to MINO, new quinolones and VCM. These epidemic strains were also isolated from the nose of medical staff and from air samples in the wards. These findings suggest that the hospital environment including the patients and hospital personnel is extensively contaminated with multi-resistant MRSA of coagulase type II. Measures should be taken for prevention and control of nosocomial infection with MRSA in the whole hospital.