Pulsed-field gel electrophoresis for analysis of comparatively mega-base sized chromosomal restriction fragments is an important molecular technique in the epidemiological study of a variety of nosocomial pathogens. The usefulness of this approach is demonstrated in the evaluation of Staphylococcus aureus isolates exhibiting decreased susceptibility to teicoplanin in two clinical settings: multiple cultures from a single patient and isolates from different patients within the same hospital.