The lysostaphin sensitivity test of staphylococci is a reliable classification method based on the differences in peptidoglycan compositions. Lysostaphin sensitive staphylococci are identified as S. aureus. In this paper, we stueied the applicability of this test to the rapid classification of clinically isolated staphylococci. Staphylococci were exposed to 2μg of lysostaphin per ml at 37℃ for 15 min. The sensitivity was decided by a turbidity check and gram-stain check. There were no differences between the check methods. Sixty-four strains of 99 clinical isolates were sensitive and consisted of 59 S. aureus. strains and 5 non-S. aureus strains (S. simulans 4; S. capitis 1). The 35 strains which were lysostaphin-insensitive were non-S. aureus as identified by coagulase and other biological sensitivity tests. The lysostaphin sensitivity test might be a very reliable and rapid method for the identification of S. aureus.