Gram-positive bacteria have become more important as a source of both community and nosocomial infection in the United States during the past few -years. In part, this has been due to the increasing prevalence of resistance of some of these organisms to commonly-employed antimicrobials. Initially, such resistance was seen primarily in university and referral hospitals. Spread of resistant strains to the community hospital recently has become prominent for many of these organisms. Exemplifying these trends are methicillin-resistance in Staphylococcus aureus , vancomycin-resistance in coagulase-negative staphylococci, relative resistance to penicillin among pneumococci, aminogrycoside-resistance in viridans streptococci, and resistance to both β -lactams and aminoglycosides in enterococci. These developments highlight the importance of the Gram-positive cocci in today's clinical practice in the USA. The need to define and deal with these trends is emphasized by the speed with which the changes have developed in both university and community hospitals.