Staphylococcus aureus colonization is common in atopic dermatitis (AD) and can exacerbate the disease. Some patients with atopic dermatitis may act as a reservoir for S. aureus transmission to others. This study compared S. aureus colonization in atopic dermatitis patients and their caregivers with control patients and their caregivers. Quantitative cultures were obtained from the lesions, clinically normal skin, hands, and anterior nares of 100 patients with atopic dermatitis, 100 controls with other cutaneous disorders, and 200 caregivers. The AD patients had significantly greater presence of S. aureus from lesional and clinically normal skin, as well as the hand. Significantly increased carriage of S. aureus was found in the anterior nares of caretakers of AD patients compared with control caretakers. Topical corticosteroid use did not affect recovery of S. aureus. There was a significant correlation between recovery of S. aureus from lesional skin and recovery from the anterior nares and hands. The nares and hands may be important reservoirs and vectors for autotransmission of S. aureus to lesional skin and for transmission to patients with AD.