Objectives - We describe the investigation and control of an outbreak of Staphylococcus aureus (SA) skin infections—carrying the gene encoding Panton-Valentine leukocidin [SA PVL(+)]—that occurred in 2006 at an elementary school. Patients and methods - Among teachers, students, and their contacts, skin infections that appeared at the start of the school year were diagnosed and treated at the hospital, where screening for nasal colonization by SA was also conducted. A case of infection was defined as a person who developed folliculitis, abscesses, or boils, with SA PVL(+) isolated from a skin or nasal swab. Colonization was defined as the isolation of SA PVL(+) from a nasal swab, without skin lesions. In addition to the recommended control measures, treatment with intranasal mupirocin was extended to colonized individuals and to those in close contact with infected cases. Results - Over five months, 22 cases of SA PVL(+) skin infections were confirmed in 15 elementary school students (incidence rate: 18.5%) and seven members of their immediate families. The prevalence of nasal colonization among non-schooled family members in this school increased steadily from 0.0% to 30.0% depending on the number of skin infection cases in the family (p < 0.01). Two-thirds of those treated with mupirocin were decolonized. Conclusion - School and family transmission of this SA strain confirms the epidemic potential of PVL(+) isolates. Screening for nasal colonization should be limited to cases of skin infection and their close contacts. (R.A.)