BACKGROUND: The use of personal digital assistants (PDAs) by health care workers is increasing. Increasing rates of infection in our institution led to the question of whether PDAs were colonized with pathogenic organisms. METHODS: Specimens for culture were obtained from PDAs used at our institution, and surveys were distributed to the users to determine factors predisposing to colonization. RESULTS: Forty percent of PDAs had growth on culture. The most common organism detected on 27 of 82 PDAs was coagulase-negative Staphylococcus (82%). No isolates of methicillin-resistant Staphylococcus aureus or vancomycin-resistant enterococci were detected. Colonization was more common on PDAs that had undergone previous cleaning. No other predisposing factors to colonization were found. CONCLUSIONS: PDAs are frequently colonized with typical skin organisms and less commonly with pathogenic organisms. Whether PDAs used in the health care setting serve as vectors for nosocomial infection is not determined.