In a prospective study involving 115 patients with methicillin-resistant Staphylococcus aureus nares carriage, we found that skin and environmental contamination with methicillin-resistant S. aureus was as likely among individuals whose S. aureus carriage was identified only through active surveillance as it was among those individuals whose S. aureus carriage was identified clinically, which suggests that strategies to limit transmission must address colonized patients, as well as infected patients.