Frequencies of different staphylococcal nasal carrier classes were studied in groups of students of nursing and of laboratory personnel in Cologne, West Germany, and in Krakow, Poland, by six consecutive samplings of their nasal vestibules. The general number of persistent carriers of S. aureus appeared to be lower than in previous studies, paralleling the diminished numbers of staphylococcal infections in populations. Differences in numbers of persistent carriers between the Cologne and Krakow groups were probably related to the incidence and types of S. aureus in the environment.